Question

数学方程式简化1.(3x-4)(2x+7) 2.(x^2-y)(x^2+y)(x^4+y^2) 3.(a-1)(a^3-

Answer 1

1.(3x-4)(2x+7)=6x^2+21x-8x-28=6x^2+13x-28

2.(x^2-y)(x^2+y)(x^4+y^2)=(x^4-y^2)(x^4+y^2)=x^8-y^2

3.(a-1)(a^3-3a^2+3a-1)

=a^4-3a^3+3a^2-a-a^3+3a^2-3a+1

=a^4-4a^3+6a^2-4a+1

4.(2x^+3)(x-7)-(x+4)(x^2-1)

=2x^3-14x^2+3x-21-(x^3-x+4x^2-4)

=x^3-18x^2+4x-17