Tìm x: a) x - 12 = 14 b) 2x - 13 = 3.17

* Hướng dẫn giải

a)

 $\begin{array}{l}x-12=14\\ x=14+12\\ x=26\end{array}$

b)

 $\begin{array}{l}2\mathrm{x}-13=3.17\\ 2\mathrm{x}=51+13\\ 2\mathrm{x}=64\\ x=64:2\\ x=32\end{array}$

c)

 $\begin{array}{l}x-43=2.18\\ x=36+43\\ x=79\end{array}$

d)

 $\begin{array}{l}\left(x-14\right).39=0\\ x-14=0\\ x=14\end{array}$

e) 

$\begin{array}{l}\left(13-x\right).28=28\\ 13-x=28:28\\ 13-x=1\\ x=13-1\\ x=12\end{array}$

f)

$\begin{array}{l}22.\left(35-x\right)=22\\ 35-x=1\\ x=35-1\\ x=34\end{array}$

g)

 $\begin{array}{l}x-24:2=18\\ x-12=18\\ x=40\end{array}$

h)

$\begin{array}{l}400+\left(275-x\right)=570\\ 275-x=570-400\\ 275-x=170\\ x=275-170\\ x=105\end{array}$