Question

if a=3x 5x-6 and b= -2x^2-6x 7 then a-b equals

Answer 1

some signs are missing so I will assume that
a=3x^2+5x-6 and b=-2x^2-6x+7 so

a-b=3x^2+5x-6-(-2x^2-6x+7)
don't forget the invisible -1 in front of the parenthasees to help distribute
3x^2+5x-6+2x^2+6x-7
add like terms
5x^2+11x-13