Đáp án:
c. \(x = - \dfrac{7}{5}\)
Giải thích các bước giải:
\(\begin{array}{l}
a.\left( {3x - 5} \right)\left( {5x - 7} \right) + \left( {5x + 1} \right)\left( {2 - 3x} \right) = 4\\
\to 15{x^2} - 21x - 25x + 35 + 10x - 15{x^2} + 2 - 3x = 4\\
\to - 39x = - 33\\
\to x = \dfrac{{33}}{{39}}\\
b.{x^2} - \dfrac{x}{2} + 6x - 3 - 3 = {x^2} - \dfrac{x}{2}\\
\to 6x = 6\\
\to x = 1\\
c.2{x^2} + 3x - 2x - 3 - 2\left( {{x^2} + 3x + 2} \right) = 0\\
\to 2{x^2} + x - 3 - 2{x^2} - 6x - 4 = 0\\
\to - 5x = 7\\
\to x = - \dfrac{7}{5}
\end{array}\)
