Solved the system by substitutionif the system is inconsiste

Solved the system by substitution.if the system is inconsistent and has no solution,state this .if the system is dependent,write the form of the solution for any real number x.

(1) x=4y+3
2x+5y=-7

(2) x=-2/3y+3/4
12x+8y=6

(3)y=5x+2
y=9x-6

(4)2x-y=-15
5x+6y=5

Solution

1) x=4y+3
2x+5y=-7
2(4y+3)+5y=-7
8y+6+5y=-7
13y+6=-7
13y=-6-7
13y=-13
y=-1
x=4(-1)+3
x=-4+3
x=-1
(-1,-1)
check: 2(-1)+5(-1)=-7
-2+(-5)=-7
-7=-7
  
-1=4(-1)+3
-1=-4+3
-1=-1
4) 2x-y=-15
5x+6y=5
  
2x-y=-15
-y=-2x-15
y=2x+15
substitute now
5x+6(2x+15)=5
5x+12x+90=5
17x+90=5
17x=-85
x=-5
5x+6y=5
5(-5)+6y=5
-25 +6y=5
6y=30
y=5
solution: (-5,5)