Question

I have absolutely no idea how to factor the following:

b² + 4b = 4b²

I think you subtract 4b² from both sides:

3b² + 4b = 0

Then

b(3b + 4) = 0

Then

b = 0 and b = -4/3

Is this correct?

Thank you.

Answer 1

Your first step is wrong. Just subtract b². It should be
4b = 3b²
3b² - 4b = 0
b(3b-4) = 0
b=0 or b=4/3

b = -4/3 should immediately be seen not to work, since you have

b² + 4b = 4b²
If b is negative, there is no way you could subtract something from b² and wind up with 4b².

Answer 2

Thank you Steve! I see where I made my mistake.