(2a + 1) / (56a^2 - 4a - 12)

We want to factor 56a^2 - 4a - 12, hopefully with 2a + 1 as a factor.

(2a + 1)(?a + ??) = 56a^2 - 4a - 12

The ? has to be 28 so that 2a * 28a = 56a^2

(2a + 1)(28a + ??) = 56a^2 - 4a - 12

The ?? has to be -12 so that 1 * ?? = -12

(2a + 1)(28a - 12) = 56a^2 - 4a - 12

Is this true? Let's do FOIL to make sure.

56a^2 - 24a + 28a - 12

56a^2 + 4a - 12

56a^2 + 4a - 12 is not equal to 56a^2 - 4a - 12.

That means 2a+1 is not a factor of 56a^2 - 4a - 12.

There's no 2a+1 to factor out on the bottom, which means we can't cancel out the 2a+1 on the top, which means. . . there's nothing to do.

(2a + 1) / (56a^2 - 4a - 12) doesn't reduce.

Are you sure the problems shows -4a instead of +4a?