Solve the following system of simultaneous linear equations by the substitution method:

x + y = 14

x - y = 4

Solve the following system of simultaneous linear equations by the substitution method:

2x + 3y = 9

3x + 4y = 5

Solve the following system of simultaneous linear equations by the substitution method:

3x - 5y = 4

9x - 2y = 7

Solve the following system of simultaneous linear equations by substitution method:

3x - 5y = -2

7x - 3y = -9