Question

What is the y-intercept of `y=-2(8-x)-9`?

Answer 1

`color(blue)(-25)`

Explanation:

The `y` intercept occurs where `x=0`

`:.`

`y=-2(8-(0))-9`

`y=-16-9`

`color(blue)(y=-25)`

Answer 2

`-25`

Explanation:

Expand the bracket

`-2(8-x)`

so

`y = -2 (8 - x) - 9`

becomes

`y = - 16 + 2x - 9`

Now,

`- 16 - 9 = - 25`

so

`y = - 16 + 2x - 9`

becomes

`y = 2x - 25`

The slope-intercept equation of a straight line is

`y = mx + c`

where `m` is the gradient of the line and `c` is the `y`-intercept. So your answer is `- 25`.