please help

Question

Use substitution to solve the following system of equations:

 

4x-y=5

2x+3y=-8

Answer 1

 

 

4x-y=5                       ...........1

  

2x+3y=-8                  ............2

 

 

equation 1

 

4x-y=5

 

subtract 4x from both sides

 

-y=5-4x

 

multiply by -1 to both sides

 

y=-5+4x

 

y= 4x-5

 

substitute this in equation 2

 

2x+3y=-8

2x+3(4x-5)=-8

 

2x+12x-15=-8

combine like terms and subtract 15 from both sides

 

14x=7 

 

x=1/2

 

substitute this value of x in equation 1

 

4x-y=5

4(1/2)-y=5

 

2-y=5

 

-y=3

y=-3