Question

Giải phương trình

A. (x²-5x)² + 10(x² -5x) +24

B. x(x+1)(x-1)(x+2) = 24

C. (x²-6x +9)² -15( x²-6x + 10) = 1

Answer 1

a: \(\left(x^2-5x\right)^2+10\left(x^2-5x\right)+24\)

\(=\left(x^2-5x+4\right)\left(x^2-5x+6\right)\)

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

b: \(x\left(x+1\right)\left(x-1\right)\left(x+2\right)=24\)

\(\Leftrightarrow\left(x^2+x\right)\left(x^2+x-2\right)=24\)

\(\Leftrightarrow\left(x^2+x\right)^2-2\left(x^2+x\right)-24=0\)

\(\Leftrightarrow x^2+x-6=0\)

=>(x+3)(x-2)=0

=>x=-3 hoặc x=2