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Wiskunde

Graad 9

Getalpatrone

Grafiese voorstellings

Vergelykings

Statistiek

Waarskynlikheidsleer

Module 16

Om eenvoudige probleme op te los deur vergelykings te vorm

Aktiwiteit 1

Om eenvoudige probleme te doen deur vergelykings te vorm en op te los

[lu 2.2, 2.4]

Hoe word hierdie probleem gedoen?

Jamie se pa is vier keer so oud as Jamie. Sy pa is 40; hoe oud is Jamie?

a) Miskien moet ons baie hard dink en ‘n paar raaiskote waag, soos: As Jamie 1 is, is sy pa 4. Nie reg nie. Wat van 2 jaar oud? Ensovoorts.

b) Maak ‘n tabel en voltooi die spasies. Help dit?

Ouderdom 1 2 3 4
Ouderdom х 4 4 8 12 28 40

c) Teken ‘n vloeidiagram. Help dit?

  • Daar is duidelik nie veel verskil tussen die drie metodes nie – jy kan enigeen gebruik wat jou pas. Hulle is egter nie van veel waarde nie, want jy moet nog so baie raai. Vir moeiliker probleme word hierdie metodes onmoontlik om te gebruik.
  • Gelukkig is daar ‘n beter manier.
  • Die beste metode om hierdie probleem aan te pak is om ‘n vergelyking vanuit die inligting te vorm. Dan los ons die vergelyking op en skryf die antwoord neer uit die oplossing van die vergelyking.
  • Dis moeilik om vergelykings te vorm, maar dit word makliker met oefening.
  • Vir ‘n vergelyking benodig ons ‘n gelykaanteken en ‘n veranderlike (ons gebruik dikwels x , maar dit kan enige letter wees).

Jamie se pa is vier keer so oud as Jamie. Sy pa is 40; hoe oud is Jamie?

  • In die algemeen lyk die vergelyking so:
  • Vier maal Jamie se ouderdom = vader se ouderdom wat 40 is.
  • Die vraag vereis Jamie se ouderdom; dus: Laat Jamie se ouderdom x wees .
  • Nou word die vergelyking: 4 x = 40
  • Ons moet ‘n getal vind wat 40 gee as ons dit met 4 vermenigvuldig. As ons 40 deur 4 deel, is die antwoord 10. Dus moet х 10 wees, en Jamie is dus 10 jaar oud. Dis maklik om te bevestig dat dit die korrekte antwoord is.

‘n Probleem vir jou: Leon het 48 albasters. Amy het slegs ‘n derde soveel as Leon; hoeveel het sy? Gebruik die vorige metode.

Sit jou antwoord op hierdie manier uiteen:

Wat stel die veranderlike voor?.

  • Skryf ‘n vergelyking met hierdie veranderlike.
  • Los die vergelyking op.
  • Skryf die oplossing neer, m.a.w. wat die waarde van die veranderlike is.
  • Skryf die antwoord op die probleem in woorde neer.

Let op dat die eerste stap en laaste stap in woorde is, en die middelste stappe, algebra.

Oefening:

Vind die antwoorde op die volgende probleme:

1. Mnr. Jacobs het R295,45 in sy sak. Mev. Jacobs het R55,30 minder as haar man in haar handsak. Wat is die bedrag in haar handsak?

2. Ek dink aan ‘n getal. Ek vermenigvuldig dit met 7 en deel die antwoord deur 3. Die resultaat is 49. Wat is die getal waaraan ek gedink het? Onthou om jou antwoord te kontroleer.

3. In Amerika koop Joanie ‘n item wat $5,75 kos. Sy bereken dat dit R41,69 is as sy dollars na rande omskakel. Wat is die dollar–rand wisselkoers wat sy gebruik het?

Aktiwiteit 2

Om doeltreffende metodes te ontwikkel vir moeiliker probleme

[lu 2.3, 2.4]

  • Ons gaan nog woordsomme doen, maar ons gaan eers op die algebra in die oplossing konsentreer. Maak telkens seker dat jy weet wat elke stap beteken, en waarom dit gedoen word.
  • Party van die volgende probleme word deur hul oplossings gevolg. Probeer eers om self by die antwoord uit te kom voor jy verder lees. Vergelyk dan jou antwoord en die manier waarop jy dit uiteensit.

Questions & Answers

how does Neisseria cause meningitis
Nyibol Reply
what is microbiologist
Muhammad Reply
what is errata
Muhammad
is the branch of biology that deals with the study of microorganisms.
Ntefuni Reply
What is microbiology
Mercy Reply
studies of microbes
Louisiaste
when we takee the specimen which lumbar,spin,
Ziyad Reply
How bacteria create energy to survive?
Muhamad Reply
Bacteria doesn't produce energy they are dependent upon their substrate in case of lack of nutrients they are able to make spores which helps them to sustain in harsh environments
_Adnan
But not all bacteria make spores, l mean Eukaryotic cells have Mitochondria which acts as powerhouse for them, since bacteria don't have it, what is the substitution for it?
Muhamad
they make spores
Louisiaste
what is sporadic nd endemic, epidemic
Aminu Reply
the significance of food webs for disease transmission
Abreham
food webs brings about an infection as an individual depends on number of diseased foods or carriers dully.
Mark
explain assimilatory nitrate reduction
Esinniobiwa Reply
Assimilatory nitrate reduction is a process that occurs in some microorganisms, such as bacteria and archaea, in which nitrate (NO3-) is reduced to nitrite (NO2-), and then further reduced to ammonia (NH3).
Elkana
This process is called assimilatory nitrate reduction because the nitrogen that is produced is incorporated in the cells of microorganisms where it can be used in the synthesis of amino acids and other nitrogen products
Elkana
Examples of thermophilic organisms
Shu Reply
Give Examples of thermophilic organisms
Shu
advantages of normal Flora to the host
Micheal Reply
Prevent foreign microbes to the host
Abubakar
they provide healthier benefits to their hosts
ayesha
They are friends to host only when Host immune system is strong and become enemies when the host immune system is weakened . very bad relationship!
Mark
what is cell
faisal Reply
cell is the smallest unit of life
Fauziya
cell is the smallest unit of life
Akanni
ok
Innocent
cell is the structural and functional unit of life
Hasan
is the fundamental units of Life
Musa
what are emergency diseases
Micheal Reply
There are nothing like emergency disease but there are some common medical emergency which can occur simultaneously like Bleeding,heart attack,Breathing difficulties,severe pain heart stock.Hope you will get my point .Have a nice day ❣️
_Adnan
define infection ,prevention and control
Innocent
I think infection prevention and control is the avoidance of all things we do that gives out break of infections and promotion of health practices that promote life
Lubega
Heyy Lubega hussein where are u from?
_Adnan
en français
Adama
which site have a normal flora
ESTHER Reply
Many sites of the body have it Skin Nasal cavity Oral cavity Gastro intestinal tract
Safaa
skin
Asiina
skin,Oral,Nasal,GIt
Sadik
How can Commensal can Bacteria change into pathogen?
Sadik
How can Commensal Bacteria change into pathogen?
Sadik
all
Tesfaye
by fussion
Asiina
what are the advantages of normal Flora to the host
Micheal
what are the ways of control and prevention of nosocomial infection in the hospital
Micheal
what is inflammation
Shelly Reply
part of a tissue or an organ being wounded or bruised.
Wilfred
what term is used to name and classify microorganisms?
Micheal Reply
Binomial nomenclature
adeolu
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Source:  OpenStax, Wiskunde graad 9. OpenStax CNX. Sep 14, 2009 Download for free at http://cnx.org/content/col11055/1.1
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