Câu hỏi của Quyên Lê

Question

Tìm x, biết: a)(x-3)-9.(2x-7)=-16:2      b) -2.(-1+x)+5.(-2+x)=-14+x.      Thanks mọi người nhìu nhìu <3

Rain Tờ Rym Te · Accepted Answer

a) $\left(x-3\right)-9\left(2x-7\right)=\dfrac{-16}{2}$

$\Rightarrow x-3-18x+63=-8$

$\Rightarrow x=4$

b) $-2\left(-1+x\right)+5\left(-2+x\right)=-14+x$

$\Rightarrow2+-2x-10+5x=-14+x$

$\Rightarrow x=-3$Câu trả lời: a) $\left(x-3\right)-9\left(2x-7\right)=\dfrac{-16}{2}$

$\Rightarrow x-3-18x+63=-8$

$\Rightarrow x=4$

b) $-2\left(-1+x\right)+5\left(-2+x\right)=-14+x$

$\Rightarrow2+-2x-10+5x=-14+x$

$\Rightarrow x=-3$

Mashiro Shiina · Answer

$\left(x-3\right)-9.\left(2x-7\right)=-16:2$

$\Leftrightarrow\left(x-3\right)-9\left(2x-7\right)=-8$

$\Leftrightarrow x-3-18x+63=-8$

$\Leftrightarrow x-3-18x=-8-63$

$\Leftrightarrow-17x-3=-71$

$\Leftrightarrow-17x=-68$

$\Leftrightarrow x=-68:-17=4$

$-2\left(-1+x\right)+5\left(-2+x\right)=-14+x$

$\Leftrightarrow2-2x-10+5x=-14+x$

$\Leftrightarrow-8+3x=-14+x$

$\Leftrightarrow3x-x=-14-8$

$\Leftrightarrow2x=-6\Rightarrow x=-3$Câu trả lời: $\left(x-3\right)-9.\left(2x-7\right)=-16:2$