Linear Graphs and Relations Question

[shooterblitz]

Hey guys,

Seen this type of question re-appear in nearly all trial exams.

Multiple choice question, usually shows a graph, saying the relationship shown is y against x3 (cubed).

Which graph shows the relationship between y and x?

Always stuff up that question, tends to ruin my streak. How can I get across this question?

[b^3]

I'll take q7 of the linear module as an example. http://www.vcaa.vic.edu.au/Documents/exams/mathematics/2007furmath1.pdf

Now we have a straight line on an axis with vs . Since we have a straight line, we effectively have , where is our dependent variable and is our independent variable. So that is . So how do we find ? Well it's just the gradient of our straight line, which is , so . Now which curve is this? Since all the options have the same shape as a curve, we need to substitute in the given value at each point and see what comes out.
, , so we have the point , so option C.

You could also do something with looking at what the point given becomes, but as in this situation we won't always get the same point, but rather another point on the curve.