Question

How do you determine the x and y intercepts of `y=-x^2-3x+18`?

Answer 1

To find the `y`-intercept, we set `x=0`,

`y=-(0)^2-3(0)+18=18`

Hence, the `y`-intercept is `18`.

To find the `x`-intercepts, we set `y=0`,

`0=-x^2-3x+18`

by multiplying by `-1`,

`0=x^2+3x-18`

by factoring out,

`0=(x+6)(x-3) => x=-6,3`

Hence, the `x`-intercepts are `x=-6, 3`.

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I hope that this was helpful.