How do you write the linear function whose x intercept a and y intercept b are given: a= -1 b=-2?

1 Answer
Peter
May 7, 2016

y= -2x - 2

Explanation:

Given x - intercept is a = -1, coordinate of x-intercept is (-1, 0)
and y-intercept is b= -2, coordinate of y-intercept is (0,-2)

Find the gradient of the function,

Gradient = (rise)/(run)riserun
= (triangley)/(triangle x)△y△x
= ( (-2) - 0 ) / ( 0 - (-1)(−2)−00−(−1)
= -2/1−21
= -2
Hence the gradient is -2.

A linear function has the form : y = mx + c
where m is the gradient and c is a constant.
You found m, but not c.

To find c the constant, substitute m, and a point ( a coordinate) say the x-intercept (-1, 0) into the form y =mx + c,

0 = (-2)(-1) + c(−2)(−1)+c
c = -2

Hence the linear function has the equation y= -2x - 2

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