b = (a - 3)²
Our aim is to get <u><em>a</em></u> to be alone
1) First we get rid of what's in the brackets. So we subtracts each side by 3. Of course, the opposite of subtracting is adding:
b+3 = a²
2) Now we get rid of the squared in a. Opposite of squaring is square rooting.
3) There we have it. a is now by itself. We can test if we're right by substituting.
Lets make a=2
b=(a-3)²
b= (2-3)²
b= 1
NOW: