a) 12x + 69 - 23 = 109
12x + 46 = 109
12x = 63
x = 21/4
b) 56/x + 49 = 7
56/x = -42
x = 56/-42
x = -4/3
12x+69-23=109
12x+69=109+23
12x+69=132
12x-132-69
12x=63
x=63/12
x=21/4
56/x+49=7
x+49=56/7
x+49=8
x=8-49
x=-41
kick nha minh nhanh nhat
\(12x+69-23=109\)
\(\Rightarrow12x+46=109\)
\(\Rightarrow12x=63\)
\(\Rightarrow x=\frac{63}{12}\)
\(\Rightarrow x=5,25\)
b) \(\frac{56}{x}+49=7\)
\(\Rightarrow\frac{56}{x}=-42\)
\(\Rightarrow-42x=56\)
\(\Rightarrow x=\frac{-4}{3}\)