SOLUTION: i need help to solve this equation using the substitution method 4x-y= -1 3x+2y= 13

Algebra ->  Expressions-with-variables -> SOLUTION: i need help to solve this equation using the substitution method 4x-y= -1 3x+2y= 13      Log On


   



Question 661770: i need help to solve this equation using the substitution method
4x-y= -1
3x+2y= 13

Answer by ankor@dixie-net.com(22740) About Me  (Show Source):
You can put this solution on YOUR website!
solve this equation using the substitution method
4x-y= -1
3x+2y= 13
:
Use the 1st equation for substitution
4x - y = -1
subtract 4x from both sides
-y = -4x - 1
y has to be positive, multiply both sides by -1
y = 4x + 1
:
Replace y with (4x+1) in the 2nd equation
3x + 2(4x+1) = 13
3x + 8x + 2 = 13
subtract 2 from both sides
3x + 8x = 13 - 2
11x = 11
x = 11/11
x = 1
Find y
y = 4x + 1
y = 4(1) + 1
y = 5
:
Check solution of x=1, y=5 in the 2nd equation
3x + 2y = 13
3(1) + 2(5) = 13
3 + 10 = 13