Question

(7x^2-6x-4)-(8x^2+6x-9)

Answer 1

-x^2 - 12x + 5

Answer 2

how did you get that

Answer 3

Keep in mind the minus sign in front of the second set of brackets so you get:
\[(7x ^{2} - 6x - 4) - (8x ^{2} + 6x - 9) = 7x ^{2} - 6x - 4 - 8x ^{2} - 6x + 9 \]
rearraging and putting the same powers of x together gives
\[7x ^{2} - 8x ^{2} - 6x - 6x - 4 + 9 = -x ^{2} - 12x + 5\]

Answer 4

the sign doesn't change?

Answer 5

which sign?