21 : (y+3)x4=100-88
21:(y+3)x4=12
21:(y+3)=12 :4
21:(y+3)=3
y+3=21:3
y+3=7
y=7-3
y=4
Đáp số y=4
\(21:\left(y+3\right)\times4+88=100\)
\(21:\left(y+3\right)\times4=100-88\)
\(21:\left(y+3\right)\times4=12\)
\(21:\left(y+3\right)=12:4\)
\(21:\left(y+3\right)=3\)
\(y+3=21:3\)
\(y+3=7\)
\(y=7-3\)
\(y=4\)
21 : ( y + 3 ) x 4 + 88 = 100
21 : ( y + 3 ) x 4 = 100 - 88
21 : ( y : 3 ) x 4 = 12
21 : ( y : 3 ) = 12 : 4
21 : ( y : 3 ) = 3
y + 3 = 21 : 3
y + 3 = 7
y = 7 - 3
y = 4
