Câu hỏi của Ánh Vũ Ngọc

Question

Giải các phương trình sau:

a, $\dfrac{3\left(5x-2\right)}{4}-2=\dfrac{7x}{3}-5\left(x-7\right)$

b, $\dfrac{x+5}{2}+\dfrac{3-2x}{4}=x-\dfrac{7+x}{6}$

c, \(\dfrac{x-3}{11}+\dfrac{x+1}{3}=\dfrac{x...

lê thị hương giang · Accepted Answer

$a,\dfrac{3\left(5x-2\right)}{4}-2=\dfrac{7x}{3}-5\left(x-7\right)$

$\Leftrightarrow\dfrac{15x-6-8}{4}=\dfrac{7x-15\left(x-7\right)}{3}$

$\Leftrightarrow\dfrac{15x-14}{4}=\dfrac{7x-15x+105}{3}$

$\Leftrightarrow\dfrac{45x-42}{12}=\dfrac{-32x+420}{12}$

$\Leftrightarrow45x+32x=420+42$

$\Leftrightarrow77x=462$

$\Leftrightarrow x=6$

$b,\dfrac{x+5}{2}+\dfrac{3-2x}{4}=x-\dfrac{7+x}{6}$

$\Leftrightarrow\dfrac{2x+10+3-2x}{4}=\dfrac{6x-7-x}{6}$

$\Leftrightarrow\dfrac{13}{4}=\dfrac{5x-7}{6}$

$\Leftrightarrow2\left(5x-7\right)=3.13$

$\Leftrightarrow10x-14=39$

$\Leftrightarrow10x=53$

$\Leftrightarrow x=5,3$

$c,\dfrac{x-3}{11}+\dfrac{x+1}{3}=\dfrac{x+7}{9}-1$

$\Leftrightarrow\dfrac{3x-9+11x+11}{33}=\dfrac{x+7-9}{9}$

$\Leftrightarrow\dfrac{14x+2}{33}=\dfrac{x-2}{9}$

$\Leftrightarrow33\left(x-2\right)=9\left(14x+2\right)$

$\Leftrightarrow33x-66=126x+18$

$\Leftrightarrow-93x=84$

$\Leftrightarrow x=-\dfrac{28}{31}$

$d,\dfrac{3x-0,4}{2}+\dfrac{1,5-2x}{3}=\dfrac{x+0,5}{5}$

$\Leftrightarrow\dfrac{3\left(3x-0,4\right)+2\left(1,5-2x\right)}{6}=\dfrac{x+0,5}{5}$

$\Leftrightarrow\dfrac{9x-1,2+3-4x}{6}=\dfrac{x+0,5}{5}$

$\Leftrightarrow\dfrac{5x+1,8}{6}=\dfrac{x+0,5}{5}$

$\Leftrightarrow5\left(5x+1,8\right)=6\left(x+0,5\right)$

$\Leftrightarrow25x+9=6x+3$

$\Leftrightarrow19x=-6$

$\Leftrightarrow x=-\dfrac{6}{19}$

$\Leftrightarrow77x=378$

$\Leftrightarrow x=\dfrac{54}{11}$Câu trả lời: $a,\dfrac{3\left(5x-2\right)}{4}-2=\dfrac{7x}{3}-5\left(x-7\right)$