Needed help with this math problem.

Question

(y - 3) (y - 6) = 0

y equals what ?

Answer 1

Harry - 

If two things multiplied together equal zero, the one of them HAS to equal zero. It helps me to think about it with normal integers at first. If I multiply 2 times any other integer (1, 2, 3, 4, etc.), then I can never get zero. Even if I use negative integers (-1, -2, -3, -4, etc.), I will get a negative number, but never zero. To get zero as the product of two numbers, one or both of those numbers MUST be zero.

In the case of your question, (y - 3) (y - 6)=0  that means that either (y - 3) or (y - 6) must equal zero. Let's set both of those expressions equal to zero and see what we get for values of y.

Set first expression equal to zero: y - 3 = 0
Add 3 to both sides to isolate y: y = 3

Set second expression equal to zero: y - 6 = 0
Add 6 to both sides to isolate y: y=6

Because we don't have any more information, we have to settle with what we have: y = 3 or 6

Answer 2

This question uses what's called the Zero Product Property. It means that if (a)(b) = 0, then either a is 0 or b is 0. (They could both be zero too).

 

So then, y-3 = 0 or y -6 = 0. Can you finish the problem now?