Question

tìm X biết :

A. 2 * X + 12 = 36 

B. ( X + 21) : 8 = 12 = 20

C. 1/2 = 3/4 * X = 3/2

dấu * này là dáu nhân các ban nhé

 

Answer 1

A) \(2x+12=36\)

\(\Leftrightarrow2x=36-12\)

\(\Leftrightarrow2x=24\)

\(\Leftrightarrow x=12\)

B) \(\left(x+21\right):8+12=20\)

\(\Leftrightarrow\left(x+21\right):8=20-12\)

\(\Leftrightarrow\left(x+21\right):8=8\)

\(\Leftrightarrow x+21=64\)

\(\Leftrightarrow x=43\)

C) \(\frac{1}{2}+\frac{3}{4}x=\frac{3}{2}\)

\(\Leftrightarrow\frac{3}{4}x=\frac{3}{2}-\frac{1}{2}\)

\(\Leftrightarrow\frac{3}{4}x=1\)

\(\Leftrightarrow x=\frac{4}{3}\)