Question

Rút gọn các biểu thức:
a) \(\left(x+1\right)^2\)- \(\left(x-1\right)^2\)- 3 ( x + 1 ) ( x - 1 )
b) 5(x + 2 ) ( x - 2 ) - \(\frac{1}{2}\)\(\left(6-8x\right)^2\)+ 17

Answer 1

b, 5(x + 2) (x - 2 ) - 1/2 (6-8x)² + 17

=5x +10 (x - 2) - 1/2 . 6 - 1/2 . 8x +17

=5x + 10x - 20 - 3 - 4x +17

=15x - 17 -4x + 17 

=15x - 4x -17 + 17

=11x - 0 =11x

Answer 2

a, (x+1)² - (x-1)² - 3(x+1) (x-1)

=(x+1)+(x-1).(x+1)-(x-1) - 3x+3x -3

=2x.0 - 3x

=-3x