Question

What is the x-coordinate of the function below when the y-coordinate is 0?

(0,5) (2,-5)

Answer 1

The equation of the function is assumed to be a straight line is of the form,

`y= mx+c`, where
`m,c`

are the gradient and the y intercept respectively.

The gradient is computed using the formula for the gradient, i.e

`m=(y_2-y_1)/(x_2-x_1) =  (-5-5)/(2-0) = -5`.

The equation of the line is,

`y= -5x+c\\=>5=-5(0)+c\\=> c= 5`

The equation of the function is ,

`y = -5x+5.`.

The value of the x-coordinate when the y coordinate is 0 is found as shown below.

`0=-5x+5\\=>x=1\\`.

so the x-coordinate is 1.