Question

How do you solve b^2=-3b

Answer 1

Answer:

b=0,-3

Step-by-step explanation:

b^2+3b=0

b(b+3)=0

b=0

b+3=0

b=-3

Answer 2

Answer:

b = 0 OR b = -3

Step-by-step explanation:

To start off with, we know that this must be a quadratic equation because there's a "^2".

Firstly, we have to bring everything over to one side of the equation. This means we have to add 3b to both sides, as we want the right-hand side to be 0.

b^2 = -3b

+3b   +3b

b^2 + 3b = 0

Secondly, we have to factorise. We need to see what number goes into both "b^2" AND "3b".

That is "b".

b^2 + 3b = 0

factor out b

b(b + 3) = 0

Thirdly, we have to use the Null Factor Law to find out what b equals. The Null  Factor Law states that if an equation equals 0, then one of the terms must either be 0, or the negative of the other number.

Hence, there are two answers.

b = 0

OR

b = -3