Expand and Simplify 6(x-1)(x+2)-(1-x)(2+x)
The answer in the book is 7x^2+7x-14
The Attempt at a Solution
I've tried several ways, but all of them give the wrong answer.
I'm not sure what to do with the negative in the middle. I know it makes everything in the bracket the opposite sign (i.e. - becomes +, + becomes -) but is that for both (1-x) AND (2+x), or just (1-x)?
I'm also not sure whether to multiply the (x+2) by 6 as well as the (1-x).
first I expanded to get 6x-6+x^2-x+2x-2-2-x+2x_x^2, which simplified to 2x^2+14x+4
then I tried expanding again, without multiplying the (x+2) by 6, and got 6x-6+x^2-x+2x-2-2-x+2x+x^2 = 2x^2+6x+2
I know this is really easy, it's my first piece of maths homework for the year, but I've spent two hours trying different ways to do this problem.