А -20-x+13=-220
-x-7=-220
-x=-220+7
-x=-213
x=213
б 240-56х=352
-56х=352-240
-56х=112
х=-2
в 5/12y-3/4=1/2 |*12
5y-9=6
5y=15
y=3
г 10.36-0.37x=7.4
-0.37x=7.4-10.36
-0.37x=-2.96
x=8
д 21х-8.4=10.5
21x=18.9
x=0.9
е 1/3x+5/6x-1=4/3 |*6
2x+5-6=8
2x=9
x=4.5