PDA

View Full Version : I am trying to solve: 2x^2 + 5x = 11x + 20



kjones
06-01-2006, 08:03 AM
I am trying to solve: 2x^2 + 5x = 11x + 20

I need help!

Thanks.

steve_b
06-01-2006, 08:40 AM
To solve:

2x^2 + 5x = 11x + 20

Since the x^2 terms tells us that this is a quadratic equation, the first step in solving quadratics is to gather all terms to one side of the equation:

2x^2 + 5x - 11x - 20 = 0

2x^2 - 6x - 20 = 0

Since all coefficients are even numbers, you can divide both sides by 2 to simplify things a bit:

x^2 - 3x - 10 = 0

Factor:

(x - 5)(x + 2) = 0

The only way for two factors to multiply together and get 0 is that one of the factors must be 0. So:

x - 5 = 0, OR, x + 2 = 0

Solving these, we get:

x = 5, OR, x = -2

You should now check these answers in the original equation to see if they make true statements.

Hope that helps...

Steve