Question

tìm x biết

( 2x - 1 ) ^ 2 - ( 4x + 1 ) ( x - 3 ) = -3

Answer 1

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

\(\Leftrightarrow4x^2-4x+1-4x^2+12x-x+3=-3\)

\(\Leftrightarrow7x=-3-1-3=-7\Leftrightarrow x=-1\)

Answer 2

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

\(\Leftrightarrow\) \(4x^2-4x+1-\left(4x^2-12x+x-3\right)=-3\)

\(\Leftrightarrow\) \(4x^2-4x+1-4x^2+12x-x+3=-3\)

\(\Leftrightarrow\) \(7x+4=-3\)

\(\Leftrightarrow\) \(7x=-7\Leftrightarrow x=\dfrac{-7}{7}=-1\)

vậy \(x=-1\)