Question

Bài 2: Giải các phương trình sau:

a. (3x + 2)(x² – 1) = (9x² – 4)(x + 1)

b. x(x + 3)(x – 3) – 5(x + 2)(x² – 2x + 4) = 0

c. x(x + 3)(x – 3) + 5(x – 3) = 0

d. (3x – 1)(x² + 2) = (3x – 1)(7x – 10)

Answer 1

\(a.\left(3x+2\right)\left(x^2-1\right)=\left(9x^2-4\right)\left(x+1\right)\)

\(\Leftrightarrow\left(3x+2\right)\left(x+1\right)\left(x-1\right)=\left(3x-2\right)\left(3x+2\right)\left(x+1\right)\)

\(\Leftrightarrow x-1=3x-2\)

\(\Leftrightarrow2x=1\)

\(\Leftrightarrow x=\dfrac{1}{2}\)

Answer 2

c: =>x-3=0

hay x=3

d: \(\Leftrightarrow\left(3x-1\right)\cdot\left(x^2+2-7x+10\right)=0\)

\(\Leftrightarrow\left(3x-1\right)\left(x-3\right)\left(x-4\right)=0\)

hay \(x\in\left\{\dfrac{1}{3};3;4\right\}\)