4x-y=5 and y=2x-3

Question

solve for x and y by the (elimination) or substitution method.

 

4x-y=5

y=2x-3

 

Show all work

Answer 1

4x-y=5

y=2x-3 

 

Re-write the second equation as 2x-y = 3 then subtract it from the first equation to eliminate the y:

 

 4x  - y =  5

-2x + y = -3                         

---------------

 2x + 0 = 2

 

x = 1

y = 2x - 3 = 2(1) - 3 = -1

 

Check:

4x-y=5

4(1)-(-1)=5

5=5

 

y=2x-3

-1=2(1)-3

-1=-1

 

CHECK!