Question

Tính

a) (x² +4x)²+9x²-6x (x²+4x) 

b) (-6x³ + 7x² - 4x + 1 ) : (-2 + 1)

c) ( x-1 )( x-2 )( 3x-4 )

Answer 1

\(a)\)

\(\left(x^2+4x\right)^2+9x^2-6x\left(x^2+4x\right)\)

\(=\left(x^2+4x\right)\left(x^2+4x-6x\right)+9x^2\)

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

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

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

\(=x^2\left(x^2+2x-8\right)+9x^2\)

\(=x^4+2x^3-8x^2+9x^2\)

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

\(=x^2\left(x^2+2x+1\right)\)

\(=x^2\left(x+1\right)^2\)

Answer 2

\(b)\)

\(\left(-6x^3+7x^2-4x+1\right):\left(-2+1\right)\)

\(=\left(-6x^3+7x^2-4x+1\right)\left(-1\right)\)

\(=6x^3-7x^2+4x-1\)

\(c)\)

\(\left(x-1\right)\left(x-2\right)\left(3x-4\right)\)

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

\(=3x^3-4x^2-9x^2+12x+6x-8\)

\(=3x^3-13x^2+18x-8\)