x + 60 = 300 + 100
=> x + 60 = 400
=> x = 400 - 60
=> x = 340
x + 60 = 300 + 100
x + 60 = 400
x = 400 - 60
x = 340
x + 60 = 300 + 100
x + 60 = 400
x = 400 - 60
x = 340
x + 60 = 300 + 100
x + 60 = 400
x = 400 - 60
x = 340
X + 60 = 300 + 100
X + 60 = 400
X = 400 - 60
X = 340
x+ 60 = 300 + 100
=> x+ 60 = 400
=> x= 340
đáp số x= 340