(1)2x=x+5
2x-x=5
x=5
(2)2x-1/2=-1/2x+2
2x+1/2x=2+1/2
(2+1/2)x=2+1/2
x=1
(3)5x+21=7-2x
5x+2x=7-21
7x=-14
x=-2
(4)11x+1=5(2x+1)
11x+1=10x+5
11x-10x=5-1
x=4