Đáp án:
Giải thích các bước giải:
\(\begin{array}{l}
B3:\\
a.3x + 10 - 2x = 0 \to x = - 10\\
b.{x^2} - 2x + 1 + {x^2} - 1 = 2\\
\to x = \frac{{1 \pm \sqrt 5 }}{2}\\
c.3{x^2} - 3{x^2} + 6x = 36\\
\to x = 6\\
d.\left( {x - 3} \right)\left[ {x + 3 - x + 3} \right] = 0\\
\to 6\left( {x - 3} \right) = 0\\
\to x - 3 = 0 \to x = 3
\end{array}\)
\(\begin{array}{l}
B4\\
a.xy\left( {14x - 21y + 28xy} \right)\\
b.\left( {x + y} \right)\left( {x - 5} \right)\\
c.\left( {x - y} \right)\left( {10x + 8} \right)\\
e.x\left( {x + 1} \right)2y\left( {x + 1} \right) = \left( {x + 1} \right)\left( {x + 2y} \right)\\
f.7x\left( {x - y} \right) - 5\left( {x - y} \right) = \left( {x - y} \right)\left( {7x - 5} \right)
\end{array}\)
