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Delete - Last Modified By: rmc at 28/04/2014 1:56:35 PM
Edit Delete - Last Modified By: rmc at 29/04/2014 1:24:53 PM
The use of linear equations to model real life situations is called Linear Modelling.
This involves understanding a worded question, using this understanding to generate a linear equation that best reflects it, and then using this equation to solve the problem or find any unknowns.
Given that we are using linear equations, it may be beneficial to draw a graph of your equations to help better understand the situation.
eg. A telephone company will charge you 30¢ per minute of your call as well as a $1.20 flagfall charge. Create an equation hat describes this and use it to calculate how much the telephone company would charge you for a 6 minute phone call.
First we allocate a pronumeral for each unknown. We will let 'C' stand for the cost and 'm' stand for the number of minutes.
We know that 30¢ per minute means we will need to multiply each minute by 0.3 dollars. We also know that there is an additional charge of $1.20 no matter how long the call.
Using this information we can write the equation as: C = 0.3m +1.2 where C is the the cost in dollars and m is the number of minutes spent on the call.
If we now substitute 6 in for the number of minutes we get:
C = 0.3(6) + 1.2
--> C = 1.8 + 1.2
--> C = 3
Therefore, the cost of a 6 minute phone call is $3.