Question

Answer 1

Lời giải:

a. $7,6x+140\text{%}x=-19,8$

$7,6x+1,4x=-19,8$

$x(7,6+1,4)=-19,8$

$x.9=-19,8$

$x=-19,8:9=-2,2$

b. $\frac{-4}{9}:x-\frac{5}{6}=3\frac{1}{6}$

$\frac{-4}{9}:x=\frac{5}{6}+3\frac{1}{6}=4$

$x=\frac{-4}{9}:4=\frac{-1}{9}$

d. (\frac{4}{7}+2x)(|x|-3)=0$

$\Rightarrow \frac{4}{7}+2x=0$ hoặc $|x|-3=0$

$\Rightarrow 2x=-\frac{4}{7}$ hoặc $|x|=3$

$\Rightarrow x=-\frac{2}{7}; x=3; x=-3$

c. 

$\frac{1}{2}x+\frac{3}{5}(x-2)=3$

$\frac{1}{2}x+\frac{3}{5}x-\frac{6}{5}=3$

$x(\frac{1}{2}+\frac{3}{5})-\frac{6}{5}=3$

$x.\frac{11}{10}-\frac{6}{5}=3$
$x.\frac{11}{10}=3+\frac{6}{5}=\frac{21}{5}$

$x=\frac{42}{11}$

e.

$(x+\frac{5}{2})(\frac{2}{5}-2x)=0$

$\Rightarrow x+\frac{5}{2}=0$ hoặc $\frac{2}{5}-2x=0$

$\Rightarrow x=-\frac{5}{2}$ hoặc $x=\frac{1}{5}$