I'll do #1 -- the others you can do the same way, and we can check your answers. Just use the distributive property and the commutative properties.
18x^2+4x-15x^2-4+13x
= 18x^2-15x^2 + 4x+13x - 4
= (18-15)x^2 + (4+13)x - 4
= 3x^2 + 17x - 4
1.18x^2+4x-15x^2-4+13x
2.2x^2+8-4x+3x-6x^2+7
3.4x^2+8x-11x=6-5x^2+2
1 answer