Tìm x a) x * 1 1/2 = 1 4/5 - 2/5 b) x * 0,75 + x * 0,25 = 5

* Hướng dẫn giải

a)

$\begin{array}{l}x\times 1\frac{1}{2}=1\frac{4}{5}-\frac{2}{5}\\ x\times \frac{3}{2}=\frac{9}{5}-\frac{2}{5}\\ x\times \frac{3}{2}=\frac{7}{5}\\ x=\frac{7}{5}:\frac{3}{2}\\ x=\frac{14}{15}\end{array}$

b)

$\begin{array}{l}x\times 0,75+x\times 0,25=5\\ x\times \left(0,75+0,25\right)=5\\ x\times 1=5\\ x=5:1\\ x=5\end{array}$