<< Chapter < Page Chapter >> Page >

A line passes through the points, ( −2 , −15 ) and ( 2, −3 ) . Find the equation of a perpendicular line that passes through the point, ( 6 , 4 ) .

y = 1 3 x + 6

Got questions? Get instant answers now!

Solving a system of linear equations using a graph

A system of linear equations includes two or more linear equations. The graphs of two lines will intersect at a single point if they are not parallel. Two parallel lines can also intersect if they are coincident, which means they are the same line and they intersect at every point. For two lines that are not parallel, the single point of intersection will satisfy both equations and therefore represent the solution to the system.

To find this point when the equations are given as functions, we can solve for an input value so that f ( x ) = g ( x ) . In other words, we can set the formulas for the lines equal to one another, and solve for the input that satisfies the equation.

Finding a point of intersection algebraically

Find the point of intersection of the lines h ( t ) = 3 t 4 and j ( t ) = 5 t .

Set h ( t ) = j ( t ) .

3 t 4 = 5 t       4 t = 9         t = 9 4

This tells us the lines intersect when the input is 9 4 .

We can then find the output value of the intersection point by evaluating either function at this input.

j ( 9 4 ) = 5 9 4          = 11 4

These lines intersect at the point ( 9 4 , 11 4 ) .

Got questions? Get instant answers now!
Got questions? Get instant answers now!

If we were asked to find the point of intersection of two distinct parallel lines, should something in the solution process alert us to the fact that there are no solutions?

Yes. After setting the two equations equal to one another, the result would be the contradiction “0 = non-zero real number”.

Look at the graph in [link] and identify the following for the function j ( t ) :

  1. y- intercept
  2. x -intercept(s)
  3. slope
  4. Is j ( t ) parallel or perpendicular to h ( t ) (or neither)?
  5. Is j ( t ) an increasing or decreasing function (or neither)?
  6. Write a transformation description for j ( t ) from the identity toolkit function f ( x ) = x .
  1. ( 0 , 5 )
  2. ( 5 ,  0 )
  3. Slope -1
  4. Neither parallel nor perpendicular
  5. Decreasing function
  6. Given the identity function, perform a vertical flip (over the t -axis) and shift up 5 units.
Got questions? Get instant answers now!

Finding a break-even point

A company sells sports helmets. The company incurs a one-time fixed cost for $250,000. Each helmet costs $120 to produce, and sells for $140.

  1. Find the cost function, C , to produce x helmets, in dollars.
  2. Find the revenue function, R , from the sales of x helmets, in dollars.
  3. Find the break-even point, the point of intersection of the two graphs C   and   R .
  1. The cost function in the sum of the fixed cost, $125,000, and the variable cost, $120 per helmet.
    C ( x ) = 120 x + 250 , 000
  2. The revenue function is the total revenue from the sale of x helmets, R ( x ) = 140 x .
  3. The break-even point is the point of intersection of the graph of the cost and revenue functions. To find the x -coordinate of the coordinate pair of the point of intersection, set the two equations equal, and solve for x .
                        C ( x ) = R ( x ) 250 , 000 + 120 x = 140 x              250 , 000 = 20 x                12 , 500 = x                          x = 12 , 500

    To find y , evaluate either the revenue or the cost function at 12,500.

    R ( 20 ) = 140 ( 12 , 500 ) = $ 1 , 750 , 000

The break-even point is ( 12,500, 1,750,000 ) .  

Got questions? Get instant answers now!
Got questions? Get instant answers now!

Questions & Answers

Three charges q_{1}=+3\mu C, q_{2}=+6\mu C and q_{3}=+8\mu C are located at (2,0)m (0,0)m and (0,3) coordinates respectively. Find the magnitude and direction acted upon q_{2} by the two other charges.Draw the correct graphical illustration of the problem above showing the direction of all forces.
Kate Reply
To solve this problem, we need to first find the net force acting on charge q_{2}. The magnitude of the force exerted by q_{1} on q_{2} is given by F=\frac{kq_{1}q_{2}}{r^{2}} where k is the Coulomb constant, q_{1} and q_{2} are the charges of the particles, and r is the distance between them.
Muhammed
What is the direction and net electric force on q_{1}= 5µC located at (0,4)r due to charges q_{2}=7mu located at (0,0)m and q_{3}=3\mu C located at (4,0)m?
Kate Reply
what is the change in momentum of a body?
Eunice Reply
what is a capacitor?
Raymond Reply
Capacitor is a separation of opposite charges using an insulator of very small dimension between them. Capacitor is used for allowing an AC (alternating current) to pass while a DC (direct current) is blocked.
Gautam
A motor travelling at 72km/m on sighting a stop sign applying the breaks such that under constant deaccelerate in the meters of 50 metres what is the magnitude of the accelerate
Maria Reply
please solve
Sharon
8m/s²
Aishat
What is Thermodynamics
Muordit
velocity can be 72 km/h in question. 72 km/h=20 m/s, v^2=2.a.x , 20^2=2.a.50, a=4 m/s^2.
Mehmet
A boat travels due east at a speed of 40meter per seconds across a river flowing due south at 30meter per seconds. what is the resultant speed of the boat
Saheed Reply
50 m/s due south east
Someone
which has a higher temperature, 1cup of boiling water or 1teapot of boiling water which can transfer more heat 1cup of boiling water or 1 teapot of boiling water explain your . answer
Ramon Reply
I believe temperature being an intensive property does not change for any amount of boiling water whereas heat being an extensive property changes with amount/size of the system.
Someone
Scratch that
Someone
temperature for any amount of water to boil at ntp is 100⁰C (it is a state function and and intensive property) and it depends both will give same amount of heat because the surface available for heat transfer is greater in case of the kettle as well as the heat stored in it but if you talk.....
Someone
about the amount of heat stored in the system then in that case since the mass of water in the kettle is greater so more energy is required to raise the temperature b/c more molecules of water are present in the kettle
Someone
definitely of physics
Haryormhidey Reply
how many start and codon
Esrael Reply
what is field
Felix Reply
physics, biology and chemistry this is my Field
ALIYU
field is a region of space under the influence of some physical properties
Collete
what is ogarnic chemistry
WISDOM Reply
determine the slope giving that 3y+ 2x-14=0
WISDOM
Another formula for Acceleration
Belty Reply
a=v/t. a=f/m a
IHUMA
innocent
Adah
pratica A on solution of hydro chloric acid,B is a solution containing 0.5000 mole ofsodium chlorid per dm³,put A in the burret and titrate 20.00 or 25.00cm³ portion of B using melting orange as the indicator. record the deside of your burret tabulate the burret reading and calculate the average volume of acid used?
Nassze Reply
how do lnternal energy measures
Esrael
Two bodies attract each other electrically. Do they both have to be charged? Answer the same question if the bodies repel one another.
JALLAH Reply
No. According to Isac Newtons law. this two bodies maybe you and the wall beside you. Attracting depends on the mass och each body and distance between them.
Dlovan
Are you really asking if two bodies have to be charged to be influenced by Coulombs Law?
Robert
like charges repel while unlike charges atttact
Raymond
What is specific heat capacity
Destiny Reply
Specific heat capacity is a measure of the amount of energy required to raise the temperature of a substance by one degree Celsius (or Kelvin). It is measured in Joules per kilogram per degree Celsius (J/kg°C).
AI-Robot
specific heat capacity is the amount of energy needed to raise the temperature of a substance by one degree Celsius or kelvin
ROKEEB
Got questions? Join the online conversation and get instant answers!
Jobilize.com Reply
Practice Key Terms 5

Get Jobilize Job Search Mobile App in your pocket Now!

Get it on Google Play Download on the App Store Now




Source:  OpenStax, Precalculus. OpenStax CNX. Jan 19, 2016 Download for free at https://legacy.cnx.org/content/col11667/1.6
Google Play and the Google Play logo are trademarks of Google Inc.

Notification Switch

Would you like to follow the 'Precalculus' conversation and receive update notifications?

Ask