Ta có : 91-(27+x)=38
<=>91-27-x=38
<=>91-27-38=x
<=>x=26
39+(x-17)=72
<=>39+x-17=72
<=>x=72+17-39
<=>x=50
Tk mình nha!
\(91-\left(27+x\right)=28\)
\(27+x=91-28\)
\(27+x=63\)
\(x=63-27\)
\(x=36\)
\(39+\left(x-17\right)=72\)
\(x-17=72-39\)
\(x-17=33\)
\(x=33+17\)
\(x=50\)
hok tốt
91 - (27 + x) = 38
91 - 27 + x = 38
91 + x = 38 + 27
91 + x = 65
x = 91 - 65
x = 26
39 + (x - 17) = 72
39 + x - 17 = 72
x - 17 = 72 - 39
x - 17 = 33
x = 33 + 17
x = 40
