Bài này khử mẫu sẽ tính nhanh hơn.
\(\frac{\left[\left(4x+28\right)3+55\right]}{5}=5\)
\(\Leftrightarrow\frac{\left[\left(4x+28\right)3+55\right]}{5}=\frac{25}{5}\)
\(\Leftrightarrow\left[\left(4x+28\right)3+55\right]=25\)
\(\Leftrightarrow\left[12x+84+55\right]=25\)
\(\Leftrightarrow12x=25-84-55\)(chuyển vế đổi dấu)
\(\Leftrightarrow12x=-114\Leftrightarrow x=-\frac{19}{2}\)
\(\frac{\left[\left(4x+28\right).3+55\right]}{5}=5\)
\(\Leftrightarrow\left(4x+28\right).3+55=25\)
\(\Leftrightarrow\left(4x+28\right).3=-30\)
\(\Leftrightarrow4x+28=-10\)
\(\Leftrightarrow4x=-38\)
\(\Leftrightarrow x=-9,5\)
Vậy\(x=-9,5\)
Ddaeng
(4x+28)*3+55=5*5
(4x+28)*3+55=25
(4x+28)*3=25-55
(4x+28)*3=-30
4x+28=-30:3
4x+28=-10
4x=-10-28
4x=-38
x=-38:4
x=-9,5
\(\frac{\left(4x+28\right).3+55}{5}=5\)
\(\Leftrightarrow\left(4x+28\right).3+55=25\)
\(\Leftrightarrow\left(4x+28\right).3=-30\)
\(\Leftrightarrow4x+28=-10\)
\(\Leftrightarrow4x=-38\)
\(\Leftrightarrow x=-9,5\)
Vậy \(x=-9,5\)
