Question

Solve the following quadratic function by utilizing the square root method. y = x2 - 64​

Answer 1

`x=\pm√(y+64)`

Explanation:

All you need to do is isolate the x.

First, add 64 to both sides:

`y=x^2-64\\x^2-64+64=y+64\\x^2=y+64`

Then, take the square root of both sides:

`√(x^2)=√(y+64)\\x=\sqrt{y+64`

Actually, that is:

`x=\pm√(y+64)`

Here's the reason for that. An example would be:

`x^2=4`

Here, you'd take the square root of both sides to solve for x.

`√(x^2)=√(4)\\x=2`

Right? But X could also be a -2, because a negative times a negative is a positive.

`(-2)^2=4\\-2*-2=4\\4=4`

Therefore,
`x=2, -2` or
`x=\pm2`

`x^2=2*2=4\\x^2=-2*-2=4`