(2.61-4х):0.03+4.6=90;
(2.61-4х):0.03=90-4,6
(2.61-4х):0.03=85,5
2,61-4х=85,5*0,3
2,61-4х= 25,65
4х=2,61-25,65
4х= 23,04
х=23,04/4
х= 5,76
8.36-5.36:(0.2х+0.47х)=7.56
5.36:(0.2х+0.47х)=8,36-7,56
5.36:(0.2х+0.47х)= 0,8
0.2х+0.47х=5,36/0,8
0,67х= 6,7
х=6,7/0,67
х= 10