expand and simplify

Question

1.(x^2-3x+4)(-x^2+3x-4)
2.3(2x-5)-9(4x-5)

Answer 1

1. -x^4+3x^3-4x^2+3x^3-9x^2+12x-4x^2+12x-16
simplified form:
-x^4+6x^3-17x^2+24x-16
or
x^4-6x^3+17x^2-24x+16

2. 6x-15-36x+45
simplified form:
-30x+30
30x-30

hope it will help you. :)