Question

1. tìm x

a) x²(2x-3)-12+8x=0

b) 2(x+5)(2x-5)+(x-1)(5-2x)=0

c) 2x³-32x=0

Answer 1

a: \(x^2\left(2x-3\right)+8x-12=0\)

\(\Leftrightarrow\left(2x-3\right)\left(x^2+4\right)=0\)

=>2x-3=0

hay x=3/2

b: \(\Leftrightarrow\left(2x-5\right)\left(2x+10\right)-\left(2x-5\right)\left(x-1\right)=0\)

\(\Leftrightarrow\left(2x-5\right)\left(2x+10-x+1\right)=0\)

=>(2x-5)(x+11)=0

=>x=5/2 hoặc x=-11

c: \(\Leftrightarrow2x\left(x^2-16\right)=0\)

\(\Leftrightarrow x\left(x-4\right)\left(x+4\right)=0\)

hay \(x\in\left\{0;4;-4\right\}\)