7( 5-x)+5(x-2)=15
=> 35-7x+5x-10 =15
=>25 - 2x = 15
=> 2x =10
=> x = 5
\(7\left(5-x\right)+5\left(x-2\right)=15\)
\(\Leftrightarrow35-7x+5x-10=15\)
\(\Leftrightarrow-2x=-10\)
\(\Leftrightarrow x=5\)
\(7\left(5-x\right)+5\left(x-2\right)=15\)
\(35-7x+5x-10=15\)
\(35-12x=25\)
\(12x=10\)
\(x=\frac{5}{6}\)
7(5 - x) + 5(x - 2) = 15
35 - 7x + 5x - 10 = 15
35 - 2x - 10 = 15 (lấy -7x + 5x = -2x)
25 - 2x = 15 (lấy 35 - 10 = 25)
2x = 25 - 15
2x = 10
x = 10 : 2
x = 5
Vậy x = 5
