①45%x=1.35
②x+25%x=7.5
③80%x-20%x=0.78
④65%x-42%x=13.34
x=5;
x-60% x=100.
x-30%x=14
(x+1)÷(x+25%×16)=3:4
①70%x-25%x=90
②x÷(1-24%)=20
③90%x÷20=27
80%x+20=320