Question

Which of the following expressions below is a factor of 6m squared + 7m - 5?

A. 2m + 1

B. m + 5

C. 2m - 5

D. 3m + 5

Answer 1

Suppose we have the expression
`6m^2+7m-5`. How do you factor it?

When we have a quadratic equation ax² + bx + c, we want to find two numbers that mulitply to equal ac and add to equal b.

In this case, we want to find two numbers that multiply to equal -30 and add to equal 7. Think about the factors of -30. We're going to need one negative number and one positive to multiply and get a negative one.

In this case, they are 10 and -3.

Now we must split the middle of the equation like this:


`6m^2+10m-3m-5`

Now we factor.


`2m(3m+5)-1(3m+5)`


`\boxed{(2m-1)(3m+5)}`

The answer is D. 3m+5.