Question

How many intercepts does `y = x^2 − 9` have?

Answer 1

`y = x^2-9` has
`color(white)("XXXX")`1 y-intercept and
`color(white)("XXXX")`2 x-intercepts

Explanation:

The y-intercept(s) is/are the possible values of `y` when `x=0`
`color(white)("XXXX")` `y = (0)^2 -9`
only has one solution (`y=-9`)

The x-intercept(s) is/are the possible values of `x` when `y=0`
`color(white)("XXXX")` `0 = x^2-9`
`color(white)("XXXX")` `rarr x^2 = 9`
`color(white)("XXXX")` `rarr x=+3` or `x=-3`
(2 possible solutions)