Using grouping, factor 2 a2 - 13a + 21. You must show your work to receive credit!
y = (2a + 7)(a + 3)
y = (2a + 7)(a − 3)
y = (2a – 7)(a + 3)

A. y= (2a+7)(a+3)

You can solve this by doing process of elimination. If you look at the factor your trying to group, you can see that the constant is a positive number. And in order to get a positive number, you have to multiply a positive by a positive or a negative by a negative. The other two answer choices have it so that you multiply a negative by a positive.

If you were to check it, just multiply it.

(2a+7)(a+3)

2a^2+6a+7a+21

Combine like terms

2a^2+13a+21

If you make it a little more clear i can answer it