Solve the following system: y = x + 3; 3x + y = 19

Solution:

The given equations are a pair of linear equations which need to be solved simultaneously:

x -  y =  -3----------> (1)

3x + y = 19----------> (2) 

Solving for x if we simply ADD equations (1) and (2) we get

x -  y =  -3

3x + y = 19

4x  + 0 = 16

4x = 16

x = 4

Solving for the variable y we substitute the value of x = 4 in equation (1), we get,

4 - y = -3

y = 4 + 3

y = 7

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Solve the following system: y = x + 3; 3x + y = 19

Summary:

Solving the system of equations  1) y = x + 3 and 2) 3x + y = 19 we obtain the values of x = 4 and y = 7