Question

giup mik voi

Rút gọn biểu thức:
1) A = ( x+5)(x – 5) – 4x( x – 3)
2) B = - ( 4x + 8) – (2x +3)( 2x – 3)

Answer 1

1: \(=x^2-25-4x^2+12x=-3x^2+12x-25\)

2: \(=-4x-8-4x^2+9=-4x^2-4x+1\)

Answer 2

\(A=\left(x+5\right)\left(x-5\right)-4x\left(x-3\right)\)

\(=x^2-25-4x^2+12x\)

\(=-3x^2+12x-25\)

\(B=-\left(4x+8\right)-\left(2x+3\right)\left(2x-3\right)\)

\(=-4x-8-4x^2+9\)

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