x + 2x + 3x + 4x + 5x = x + 28
x + 2x + 3x + 4x + 5x - x = 28
14x = 28
x = 28 : 14
x = 2
x + 2x + 3x + 4x + 5x = x + 28
=> x + 2x + 3x + 4x + 5x - x = 28
=> x x ( 1 + 2 + 3 + 4 + 5 - 1 ) = 28
=> x x 14 = 28
=> x = 28 : 14
=> x = 2
Vậy x = 2
Chúc bạn học tốt !!!
\(\text{x+2x+3x+4x+5x=x+28}\)
\(\Rightarrow x+2x+3x+4x+5x+x=28\)
\(\Rightarrow16x=28\)
\(\Rightarrow x=\frac{28}{16}=\frac{7}{4}\)
x+2x+3x+4x+5x=x+28
15x=x+28
15x-x-28=0
14x-28=0
14x=28
x=2
\(x+2x+3x+4x+5x=x+28\)
\(\Leftrightarrow\left(1+2+3+4+5\right)x=x+28\)
\(\Leftrightarrow15x=x+28\)
\(\Leftrightarrow15x-x=28\)
\(\Leftrightarrow14x=28\)
\(\Leftrightarrow x=28:14\)
\(\Leftrightarrow x=2\)
Vậy x = 2
_Chúc bạn học tốt_
x+2x+3x+4x+5x=x+28
15x=x+28
15x-x=28
14x=28
x=28:14
x=2
