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