Question

a)2 . 6^4 - 3^2 .56/ 4^2 . 135

b)2/5 + x = -1/2

c)x . -1/3 - 1/12 = 1/4

d)x-2/3 = 2x +1/5

Answer 1

Lời giải:

a. \(\frac{2.6^4-3^2.56}{4^2.135}=\frac{2^5.3^4-2^3.3^2.7}{2^4.135}\\ =\frac{2^3.3^2(2^2.3^2-7)}{2^4.135}=\frac{2^3.3^2.29}{2^4.3^3.5}=\frac{29}{30}\)

b.

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

$x=\frac{-1}{2}-\frac{2}{5}=\frac{-9}{10}$

c.

$x.\frac{-1}{3}-\frac{1}{12}=\frac{1}{4}$

$x.\frac{-1}{3}=\frac{1}{4}+\frac{1}{12}=\frac{1}{3}$

$x=\frac{1}{3}: \frac{-1}{3}=-1$

d.

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

$\Rightarrow 5(x-2)=3(2x+1)$

$\Rightarrow 5x-10=6x+3$

$\Rightarrow x=-13$