200 - 18 : (372 : 3 + x - 1) - 28 = 166
=> 200 - 18 : (124 + x - 1) = 166 + 28
=> 200 - 18 : (124 + x - 1) = 194
=> 18 : (124 + x - 1) = 200 - 194
=> 18 : (124 + x - 1) = 6
=> 124 + x - 1 = 18 : 6
=> 124 + x - 1 = 3
=> 124 + x = 4
=> x = 4 - 124 = -120
200-18:(372:3+x-1)-28=166
200-18:(372:3+x-1)=166+28
200-18:(372:3+x-1)=194
18:(372:3+x-1)=200-194
18:(372:3+x-1)=6
(372:3+x-1)=18:6
(372:3+x-1)=3
(124+x-1)=3
124+x=3+1
124+x=4
x=4-124
x=-120
vậy x=-120
\(200-18\div\left(372\div3+x-1\right)-28=166\)
\(200-18\div\left(124+x-1\right)=166+18=194\)
\(18\div\left(124+x-1\right)=200-194=6\)
\(124+x-1=18\div6=3\)
\(124+x-1=4\)
\(124+x=4\)
\(\Rightarrow x=-120\)
\(200-18:\left(372:3+x-1\right)-28=166\)
\(\Leftrightarrow200-18:\left(124+x-1\right)=194\)
\(\Leftrightarrow18:\left(123+x\right)=6\)
\(\Leftrightarrow123+x=3\Leftrightarrow x=-120\)
