\(27+\left(220-6x\right).3=615\)
\(\rightarrow\left(220-6x\right).3=615-27=588\)
\(\rightarrow220-6x=588:3=196\)
\(\rightarrow6x=220-196=24\)
\(\rightarrow x=24:6=4\)
\(315-\left(x-3\right).7=210\)
\(\Rightarrow\left(x-3\right).7=315-210=105\)
\(\Rightarrow x-3=105:7=15\)
\(\Rightarrow x=15+3=18\)
Trả lời
a)27+(220-6x)3=615
(220-6x)3=615-27
(220-6x)3=588
220-6x =588:3
220-6x =196
6x =220-196
6x =24
=>x =24:6
=>x =4
b)315-(x-3)7=210
(x-3)7=315-210
(x-3)7 =105
x-3 =105:7
x-3 =15
x =15+3
x =18
c)1302-(2x+421)=503
2x+421 =1302-503
2x+421 =799
2x =799-421
2x =378
x =378:2
x =189
d)609(5x)=12
5x =609:12
5x =50,75
x =10,15
\(1302-\left(2x+421\right)=503\)
\(\Leftrightarrow2x+421=1302-503=799\)
\(\Leftrightarrow2x=799-421=378\)
\(\Leftrightarrow x=378:2=189\)
\(609.\left(5x\right)=12\)
\(\rightarrow5x=\frac{4}{203}\)
\(\rightarrow x=\frac{4}{203}:5=\frac{4}{1015}\)
