Question

Tìm x:

a) (x-2)² -(x-3)(x+3)=6

b) 4(x-3)² -(2x-1)(2x+1)=10

c) (x-4)²-(x-2)(x+2)=6

d) 9(x+1)²-(3x-2)(3x+2)=10

giúp mình vs mình tick cho , cảm mơn

Answer 1

a) Ta có: \(\left(x-2\right)^2-\left(x-3\right)\left(x+3\right)=6\)

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

\(\Leftrightarrow x^2-4x+4-x^2+9-6=0\)

\(\Leftrightarrow-4x+7=0\)

\(\Leftrightarrow-4x=-7\)

hay \(x=\frac{7}{4}\)

Vậy: \(x=\frac{7}{4}\)

b) Ta có: \(4\left(x-3\right)^2-\left(2x-1\right)\left(2x+1\right)=10\)

\(\Leftrightarrow4\left(x^2-6x+9\right)-\left(4x^2-1\right)=10\)

\(\Leftrightarrow4x^2-24x+36-4x^2+1-10=0\)

\(\Leftrightarrow-24x+27=0\)

\(\Leftrightarrow-24x=-27\)

hay \(x=\frac{9}{8}\)

Vậy: \(x=\frac{9}{8}\)

c) Ta có: \(\left(x-4\right)^2-\left(x-2\right)\left(x+2\right)=6\)

\(\Leftrightarrow x^2-8x+16-\left(x^2-4\right)-6=0\)

\(\Leftrightarrow x^2-8x+10-x^2+4=0\)

\(\Leftrightarrow-8x+14=0\)

\(\Leftrightarrow-8x=-14\)

hay \(x=\frac{7}{4}\)

Vậy: \(x=\frac{7}{4}\)

d) Ta có: \(9\left(x+1\right)^2-\left(3x-2\right)\left(3x+2\right)=10\)

\(\Leftrightarrow9\left(x^2+2x+1\right)-\left(9x^2-4\right)-10=0\)

\(\Leftrightarrow9x^2+18x+9-9x^2+4-10=0\)

\(\Leftrightarrow18x+3=0\)

\(\Leftrightarrow18x=-3\)

hay \(x=-\frac{1}{6}\)

Vậy: \(x=-\frac{1}{6}\)

Answer 2

Đùa chứ vừa làm song mà ..... 1 sp cho thịnh