Question

1. Rút gọn

a, A=(4x+3y)² + (4x-3y)²

b,B=(x-2³)-(x+2)³

c,C=(x+2y)²+2.(x+2y) (x-2y) + (x-2y)²

2. Tìm x

a, x²+12x+36=0

b,16x²-8x+1=0

c,x³+3x²+3x+1=0

Answer 1

2a) pt <=> (x + 6)^2 = 0

<=> x = -6

b) pt <=> (4x - 1)^2 = 0

<=> x = 1/4

c) pt<=> (x + 1)^3 = 0

<=> x = -1

Answer 2

Bài 1:

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

\(=16x^2+24xy+9y^2+16x^2-24xy+9y^2\)

\(=32x^2+18y^2\)

b: Ta có: \(B=\left(x-2\right)^3-\left(x+2\right)^3\)

\(=x^3-6x^2+12x-8-x^3-6x^2-12x-8\)

\(=-12x^2-24\)