Question

Thực hiện phép tính

5) (x - 2)'2 + (x - 1)(x + 5)

6) (x + 3)(x - 3) - x(23 + x)

7) (1 - 2x)(5 - 3x) + (4 - x)'2

8) (x - 2)(x + 2) - (x +3)(x - 1)

9) (x + 1)'2 + (x - 2)(x + 2) - 4x

10) (x + 2)'2 - (x + 3)(x - 3) +10

Answer 1

6: \(\left(x+3\right)\left(x-3\right)-x\left(x+23\right)\)

\(=x^2-9-x^2-23x\)

=-23x-9

7: \(\left(1-2x\right)\left(5-3x\right)+\left(4-x\right)^2\)

\(=\left(2x-1\right)\left(3x-5\right)+x^2-8x+16\)

\(=6x^2-10x-3x+5+x^2-8x+16=7x^2-21x+21\)

8: \(\left(x-2\right)\left(x+2\right)-\left(x+3\right)\left(x-1\right)\)

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

\(=x^2-4-x^2-2x+3=-2x-1\)

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

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

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

10: \(\left(x+2\right)^2-\left(x-3\right)\left(x+3\right)+10\)

\(=x^2+4x+4-x^2+9+10\)

=4x+23