Select the correct answer.

Which expression represents - 8x2 + 54x + 140 in factored form?

(x - 70) (-8x + 2)

(x + 1) (8x - 140)

(x - 8) (2x + 70)

(x + 2) (-8x + 70)

Start with what you can get rid of just by eyeballing it. All of the factors on the left have 1x as a given. So that means that on the second factor you need a minus 8x. That lets out B and C as answers.

You have 54x as the middle term. A is going to be huge on the middle term. Huge. - 8x * 70 gives you - 560x. It's far too big. That let's out A. So we are going to focus on D.

(x + 2) (-8x + 70) = - 8x^2 - 16x + 70x + 140

(x + 2) (-8x + 70) = - 8x^2 + 56x + 140

So we have the answer. Notice how most of this question was done just by looking at the answers. Some of them were eliminated by vision alone. I recommend you try this with any math question. Use your eyes before a calculator, pencil and piece of paper.

-8x2 + 54x + 140

factor out a - 2

-2 (4x^2 - 26x-70)

-2 (4x-35) (x+2)

this is the completely factored form

distribute the - 2

(-8x+70) (x+2)

Choice D