solve each system by substitution

Question

y=x+4, 3x+y=16

Answer 1

y = x + 4           [1]

3x + y = 16        [2]

 

You can take equation [1] and substitute it into equation [2], which will give you:

 

3x + y = 16

3x + (x + 4) = 16

4x + 4 = 16

 

You can now subtract 4 from both sides of the equation:

4x + 4 - 4 = 16 - 4

4x = 12

 

And now you can divide both sides of the equation by 4:

4x/4 = 12/4

x = 3

 

You can now substitute in this value into either equation [1] or [2]. I will use [1]:

 

y = x + 4

y = 3 + 4

y = 7

 

So the final solution is:

x = 3 and y = 7