Question

a,(x³+8)-(x²-4)

b,(x²+y²-5)-4(xy-2)²

c,25(4x-3)-16(5x+7)²

Answer 1

Đề gì bn

Answer 2

a, \(\left(x^3+8\right)-\left(x^2-4\right)=\left(x+2\right)\left(x^2-2x+4\right)-\left(x-2\right)\left(x+2\right)=\left(x+2\right)\left(x^2-2x+4-x+2\right)=\left(x+2\right)\left(x^2-3x+6\right)\)

 

Answer 3

a: Ta có: \(\left(x^3+8\right)-\left(x^2-4\right)\)

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

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

\(=\left(x+2\right)\left(x^2-3x+6\right)\)

c: Ta có: \(25\left(4x-3\right)^2-16\left(5x+7\right)^2\)

\(=\left(20x-15\right)^2-\left(20x+28\right)^2\)

\(=\left(20x-15-20x-28\right)\left(20x-15+20x+28\right)\)

\(=-43\left(40x+13\right)\)