Can someone help me with this two problems?

2x+4y=0
substitute y with 0
2x+4(0)=0
solve the equation
2x+0=0
2x=0
divide by 2 on both sides
x=0
4x+8y=7
substitute y with 0
4x+8(0)=7
solve the equation
4x+0=7
4x=7
divide by 4 on both sides
x=7/4 or x=1 3/4 or x=1.75
3x-7y=-29
2x+2y=6
solve the bottom equation
3x-7y=-29
x=3-y
substitute for x
3(3-y)-7y=-29
solve the equation
y=19/5
now substitute for y
x=3-[tex]\frac{19}{5}[/tex]
solve for x
x=-4/5
the possible solution of the system is the ordered pair
(x,y)=([tex]-\frac{4}{5} ,\frac{19}{5}[/tex])