\(\Rightarrow\) 139 - 99 = 720(x - 6) = 40
\(\Rightarrow\) x - 6 = 720 : 40 = 18
\(\Rightarrow\) x = 18 + 6 = 24
Vậy x = 24
mk nhanh nhất, k mik nha
720 ( x - 6 ) = 139 - 99
720 ( x - 6 ) = 40
x - 6 = 40 : 720
x - 6 = 1/18
x = 1/18 + 6
x = 109/18
\(99+720\left(x-6\right)=139\)
\(\Leftrightarrow720\left(x-6\right)=139-99\)
\(\Leftrightarrow720\left(x-6\right)=40\)
\(\Leftrightarrow x-6=720:40\)
\(\Leftrightarrow x-6=18\)
\(\Leftrightarrow x=18+6\)
\(\Leftrightarrow x=24\)
Chúc bạn học tốt nha !