4x^2 + 3(2x^2 +1 ) = 2x ( 5x - 7 )
4x^2 + 3 ( 2x^2 + 1 ) - 2x ( 5x - 7 ) = 0
4x^2 + 6x^2 + 3 - 10x^2 + 14x = 0
14x + 3 = 0
14x = -3
x= -3/14
\(4x^2+3\left(2x^2+1\right)=2x\left(5x-7\right)\)
\(4x^2+6x^2+3=10x^2-14x\)
\(10x^2-10x^2+3=-14x\)
\(\) \(3=-14x\)
\(\dfrac{-3}{14}=x\)
Vậy \(x=\dfrac{-3}{14}\)