Question

Bài 1 : tìm các giá trị của x biết :

a) \(\left(3x-5\right)\left(2x-1\right)-\left(x+2\right)\left(6x-1\right)=0\)

b) \(\left(3x-2\right)\left(3x+2\right)-\left(3x-1\right)^2=-5\)

c) \(x^2=-6x-8\)

d) \(\frac{\left(x+1\right)^2}{3}-\frac{\left(x-2\right)^2}{3}=\frac{2x+1}{2}-\frac{\left(x-3\right)^2}{6}\)

Answer 1

a) \(\left(3x-5\right)\left(2x-1\right)-\left(x+2\right)\left(6x-1\right)=0\)

⇔ \(6x^2-13x+5-6x^2-11x+2=0\)

⇔ \(24x=7\)⇔\(x=\frac{7}{24}\)

b) \(\left(3x-2\right)\left(3x+2\right)-\left(3x-1\right)^2=-5\)

⇔ \(9x^2-4-9x^2+6x-1=5\)

⇔ \(6x=10\)⇔ \(x=\frac{5}{3}\)

c) \(x^2=-6x-8\)⇔\(x^2+6x+8=0\)⇔\(\left(x+2\right)\left(x+4\right)=0\)

⇔\(\left[{}\begin{matrix}x=-2\\x=-4\end{matrix}\right.\)