# How do you solve #5q^2 + 18q = 8#?

##### 1 Answer

#### Explanation:

We can use factor by grouping to solve this problem.

But first we need to make sure that the equation is in standard form:

Therefore, subtract 8 from both sides of the equal sign.

We need to multiply the a and the c terms and see what factors of that product will add to 18.

Factors of -40 that can add to 18 is -2 and 20.

Check:

So we can expand the quadratic to

Take the GCF of the first two terms (

*Notice how the terms in the parenthesis are the same. Those terms inside of the parenthesis will be one binomial of the factored form of the quadratic.*

The outside terms of the parentheses, 4 and q, will be combined into one parenthesis: (

**The factored form is #(q + 4)(5q - 2)#**

Since it said to solve it, we need to solve for the roots or what value of q will make the expressions in the parenthesis equal to 0.

**The roots of this quadratic are 4 and #2/5#.**