\(x\) x 18 = 28 x 3,6 + 36 x 7,2
\(x\) x 18 = 28 x 3,6 + 3,6 x 72
\(x\) x 18 = 3,6 x ( 28 + 72)
\(x\) x 18 = 3,6 x 100
\(x\) x 18 = 360
\(x\) = 360 : 18
\(x\) = 20
=>x*18=36*2,8+36*7,2=360
=>x=20
\(x\times18=28\times3,6+36\times7,2\)
\(x\times18=28\times3,6+3,6\times72\)
\(x\times18=3,6\times\left(28+72\right)\)
\(x\times18=3,6\times100\)
\(x\times18=360\)
\(x=360:18\)
\(x=20\)