Question

4. Two points on a line are (-10, 1) and (5, -5). If

the y-coordinate of another point on the line is
-3, what is the x-coordinate?

Answer 1

The x-coordinate of another point is zero

Explanation:

step 1

Find the slope between the two given points

The formula to calculate the slope between two points is equal to

`m=(y2-y1)/(x2-x1)`

we have

`(-10,1),(5,-5)`

substitute in the formula

`m=(-5-1)/(5+10)`

`m=(-6)/(15)`

Simplify

`m=-(2)/(5)`

step 2

Find the x-coordinate of another point

we have

(x,-3)

we know that

If the other point is on the line, then the slope between the other point and any of the other two points must be the same

so

Find the slope between the points

`(x,-3),(5,-5)`

Remember that

`m=-(2)/(5)`

substitute in the formula

`-(2)/(5)=(-5+3)/(5-x)`

`-(2)/(5)=-(2)/(5-x)`

the denominators must be the same

`5=5-x`

`x=0`

therefore

The x-coordinate of another point is zero