Question

Answer 1

\(a,=x^2+4x-21-5x+5=x^2-x-16\\ b,=x^3-1-x^3-1=-2\)

Answer 2

a) \(\left(x-3\right)\left(x+7\right)-5\left(x-1\right)=x^2+4x-21-5x+5=x^2-x-16\)

b) \(\left(x-1\right)\left(x^2+x+1\right)-x^3-1=x^3-1-x^3-1=-2\)

Answer 3

\(a.\left(x-3\right)\left(x+7\right)-5\left(x-1\right)\)

\(=x^2+7x-3x-21-5x+5\)

\(=x^2-x-16\)

\(b.\left(x-1\right)\left(x^2+x+1\right)-x^3-1\)

\(x^3-1-x^3-1\)

\(-2\)