Объяснение:
все написано на листочку
1.
2(4+3y)-y=3
y=-1
x=4+3(-1)
x=1
(x; y)=(1; -1)
2.
5x+3(-1+4x)=14
y=-1+4*1
y=3
(x; y)=(1;3)
3.
7a+2(-1-3a)=9
a=11
b=-1-3*11
b=-34
(a; b)=(11; -34)
4.
6
Объяснение:
все написано на листочку
1.



2(4+3y)-y=3
y=-1
x=4+3(-1)
x=1
(x; y)=(1; -1)
2.



5x+3(-1+4x)=14
x=1
y=-1+4*1
y=3
(x; y)=(1;3)
3.

7a+2(-1-3a)=9
a=11
b=-1-3*11
b=-34
(a; b)=(11; -34)
4.
6