(1)2.75-5x=2[7/10],
2.75-5X+5X=2.7+5X,
2.7+5X=2.75,
5X=0.05,
X=0.01;
(2)[1/2]+1.25X=[11/20]÷[2/5],
[1/2]+1.25X=1.375,
1.25X=0.875,
X=0.7.
(1)2.75-5x=2[7/10],
2.75-5X+5X=2.7+5X,
2.7+5X=2.75,
5X=0.05,
X=0.01;
(2)[1/2]+1.25X=[11/20]÷[2/5],
[1/2]+1.25X=1.375,
1.25X=0.875,
X=0.7.