Question

Tìm x:

a) (x-2)(3x+1) - 2x = 3x(x+2)

b) (5-2x)(3x+1) + 6x(x-1) = 0

c) (3x-5)(x+1) - 2 = 3x(x-5)

d) (4x-1)(x+1) - 4x² = 3x-2

Answer 1

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

\(\Leftrightarrow3x^2+x-6x-2-2x=3x^2+6x\)

\(\Leftrightarrow3x^2+x-6x-2x-3x^2-6x=2\)

\(\Leftrightarrow-13x=2\Leftrightarrow x=-\dfrac{2}{13}\)

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

\(\Leftrightarrow15x+5-6x^2-2x+6x^2-6x=0\)

\(\Leftrightarrow7x=-5\Leftrightarrow x=-\dfrac{5}{7}\)

c,d tương tự ý a