If x= 0, becomes

If y= 4, then so y= 4 satisfies that.

But if y= -4, then so y= -4 also satisfies that. Any time you take a square root to solve a quadratic equation, you need both + and -: " .

Very good!And the second one:

Again, squaring a positive or negative number can give you the same thing- you need " ". This should be

In both cases you are taking only the "positive" solution to a quadratic.

The answers in the back of the book are:

Could someone please tell me where I am going wrong?

Regards,

evanator

If then x can be either 2 or -2: .