7,8a+5,4a=3,3;
13,2a=3,3;
a=3,3:13,2;
a=0,25.
1,3x-0,82x=6;
0,48x=6;
x=6:0,48;
x=12,5.
x-0,28x=36;
0,72x=36;
x=36:0,72;
x=50
