№152
а)
7(x-8.2)=3x+19
7x-57.4=3x+19
7x-3x=19+57.4
4x=76.4
x=19.1
б)
0.2(5x-6)+2x=0.8
x-1.2+2x=0.8
x+2x=0.8+1.2
3x=2
x=
в)
-(7y+0.6)=3.6-y
-7y-4.2=3.6-y
-7y+y=3.6+4.2
-6y=7.8
-y=1.3
y=-1.3
г)
3(2.5-2x)=13.5-14x
7.5-6x=13.5-14x
-6x+14x=13.5-7.5
8x=6
x=0.75
д)
0.6y-1.5=0.3(y-4)
0.6y-1.5=0.3y-1.2
0.6-0.3y=-1.2+1.5
0.3y=0.3
y=1
e)
0.5(4-2a)=a-1.8
2-a=a-1.8
-2a=-1.8-2
-2a=-3.8
a=1.9