How do I solve this using the Substitution Method?

first pick a pronumeral

for this one ill pick y

if 4x-3y=-14
then -3y=-14-4x
y=(-14-4x)/-3

so substitute y in the first equation for the above and we get

x+(-14x-4x)/-3=7/2
-3x-14-4x=-21/2
-7x=-21/2+14
-7x=-21/2+28/2
-7x=7/2
x=-1/2

so using the 1st equation, y would be

-1/2+y=7/2
y=7/2+1/2
y=8/2
y=4

x + y = 7/2 ...eq. [1]
4x - 3y = -14 ...eq. [2]

Solve eq. [1] for 'y'...

y = 7/2 - x ...eq. [3]

Substitute eq. [3] into eq. [2], and solve for 'x'...

4x - 3(7/2 - x) = -14
4x - 21/2 + 3x = -14
7x = 21/2 - 14
7x = 21/2 - 28/2
7x = -7/2
x = -1/2 ...[sol'n 1]

Substitute [sol'n 1] into either eq. [1] or eq. [2], and solve for 'y'...

-1/2 + y = 7/2
y = 7/2 + 1/2
y = 4 ...[sol'n 2]

Hope this helps! :-)

4 (7/2 - y) - 3y = - 14
14 - 4y - 3y = - 14
- 7y = - 28
y = 4

x = 7/2 - 4
x = - 1/2

x = - 1/2 , y = 4

x + y = 7/2
4x - 3y = -14

x + y = 7/2
x = 7/2 - y

4x - 3y = -14
4(7/2 - y) - 3y = -14
2(7) - 4(y) - 3y = -14
14 - 4y - 3y = -14
-4y - 3y = -14 - 14
-7y = -28
y = -28/-7
y = 4

x + y = 7/2
x + 4 = 7/2
x = 7/2 - 4
x = 7/2 - 8/2
x = -1/2 (-0.5)

∴ x = -1/2 (-0.5) , 4