Question

Answer 1

a: (x-1)(x+2)

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

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

b: (3+x)(x+1)

\(=3x+3+x^2+x\)

\(=x^2+4x+3\)

c: \(\left(3x^2-4\right)\left(x+3\right)\)

\(=3x^2\cdot x+3\cdot3x^2-4\cdot x-4\cdot3\)

\(=3x^3+9x^2-4x-12\)

d: (3x+5)(2x-7)

\(=6x^2-21x+10x-35\)

\(=6x^2-11x-35\)