subsitution y=-x+5 2x+y=11

Question

substitution

Answer 1

y=-x+5

2x+y=11

 

Since we already have y, substitute its value for y in the second equation.  

 

2x + (-x + 5) = 11

 

This becomes:

 

2x -x + 5 = 11

 

Combine like terms:

 

x + 5 = 11 

 

Then subtract 5 from both sides.  This becomes:

 

x= 6

 

Now replace x in the first equation.  

 

y=-x+5 

 

This becomes:

 

y= -6+5

 

Do the math and it becomes:

 

y= -1

 

So the solution is:

 

x= 6

y= -1

 

 

Answer 2

y =-x+5

 

2x+y=11

 

2x-x+5=11

 

x=6

 

y=-1

Answer 3

y = -x + 5           eq1

2x + y = 11         eq2

 

 

Substitute eq1 into eq2 so that we have an equation with only one variable.

 

2x + (-x + 5) = 11

2x - x + 5 = 11

x + 5 = 11

x = 6

 

 

Substitute this value of x into eq1.

 

y = -6 + 5

y = -1

 

 

The solution is

 

x = 6

y = -1