Question

Answer 1

Lời giải:
a.

\(\frac{1}{4}-7x=\frac{-1}{3}\)

$\Leftrightarrow 7x=\frac{1}{4}-\frac{-1}{3}=\frac{7}{12}$

$\Leftrightarrow x=\frac{7}{12}:7=\frac{1}{12}$

b.

\(|\frac{1}{3}x-2|=\frac{-1}{3}+\frac{2}{5}=\frac{1}{15}\)

\(\Rightarrow \left[\begin{matrix} \frac{1}{3}x-2=\frac{1}{15}\\ \frac{1}{3}x-2=\frac{-1}{15}\end{matrix}\right.\Rightarrow \left[\begin{matrix} x=\frac{31}{5}\\ x=\frac{29}{5}\end{matrix}\right.\)

c.

$3^{x+2}+4.3^{x+1}=7.3^6$

$3^{x+1}(3+4)=7.3^6$

$3^{x+1}.7=7.3^6$

$3^{x+1}=3^6$

$x+1=6$

$x=5$