Question

Rút gọn biểu thức

c) (x+3)² – (x+1)(x – 4)                d) x(x+2)(x – 2) – x(x – 1)²

Answer 1

a: Ta có: \(\left(x+3\right)^2-\left(x+1\right)\left(x-4\right)\)

\(=x^2+6x+9-x^2+3x+4\)

\(=9x+13\)

b: Ta có: \(x\left(x+2\right)\left(x-2\right)-x\left(x-1\right)^2\)

\(=x\left(x^2-4\right)-x\left(x^2-2x+1\right)\)

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

\(=2x^2-5x\)

Answer 2

c) (x+3)²-(x+1)(x-4)

=x²+6x+9-(x²-3x+4)

=x²+6x+9-x²+3x-4

=9x+5

Answer 3

d)x(x+2)(x-2)-x(x-1)²

=x(x²-4)-x(x²-2x+1)

=x(x²-4-x²+2x-1)

=x(2x-5)

=2x²-5x