SOLUTION: Solve by addition 2x-3y=-2 5x=2y-9 I did... 5x=2y-9 I triex to make the equation in Ax+By=c form. So I added 2y and I got 5x+2y=-9 And since 2x-3y=-2 was already in th

Algebra ->  College  -> Linear Algebra -> SOLUTION: Solve by addition 2x-3y=-2 5x=2y-9 I did... 5x=2y-9 I triex to make the equation in Ax+By=c form. So I added 2y and I got 5x+2y=-9 And since 2x-3y=-2 was already in th      Log On


   

Question 949213: Solve by addition
2x-3y=-2
5x=2y-9
I did... 5x=2y-9 I triex to make the equation in Ax+By=c form. So I added 2y and I got 5x+2y=-9
And since 2x-3y=-2 was already in the ax+by=c form I did 5x+2y=-9(-2) and 2x-3y=-2 (5) and I got -10x-4y=18
10x-15y=-10
The -10x and 10x cancel out so I added -4y and -15y and got -19y= 8 I then divided by -19y and got Y= 8/-19
PLEASE HELP ME.. I AM STUCK AND PLEASE SHOW HOW TO CHECK MY ANSWERES.
Thank you
Found 2 solutions by rothauserc, Alan3354:
Answer by rothauserc(4718) About Me  (Show Source):
You can put this solution on YOUR website!
2x -3y = -2
5x = 2y -9
******
rewrite the second equations as
5x -2y = -9
now multiply the new second equation by -1
-5x +2y = 9
now add this new equation to the first equation
-3x -y = 7
add 3x to both sides of =
-y = 3x + 7
multiply both sides of = by -1
y = -3x -7
now substitute for y in first equation
2x -3(-3x-7) = -2
2x +9x +21 = -2
11x = -23
x = −2.09090909
using first equation substitute for x and solve for y
(2*−2.09090909) -3y = -2
−4.18181818 -3y = -2
-3y = 2.18181818
y = -0.727272727
therefore our solution is x = −2.09090909 and y = 0.727272727
*********
check our solution by substituting for x and y in second equation
(5*−2.09090909) = (2*-0.727272727) -9
−10.45454545 = −10.454545454
our answer checks



Answer by Alan3354(69443) About Me  (Show Source):
You can put this solution on YOUR website!
Solve by addition
2x-3y=-2
5x=2y-9
I did... 5x=2y-9 I triex to make the equation in Ax+By=c form. So I added 2y and I got 5x+2y=-9
****** You should have subtracted 2y --> 5x-2y = -9 ********
===============================


2x -3y = -2
5x = 2y -9 --> 5x - 2y = -9
-------------------
Multiply the 1st eqn by -2 and the 2nd by 3
-4x + 6y = 4
15x - 6y = -27
------------------ Add
11x = -23
x = -23/11
-----
Sub for x in any eqn to find y
2x -3y = -2
-46/11 - 3y = -2
3y = -46/11 + 2 = -24/11
y = -8/11
==============
2x -3y = -2 --> -46/11 + 24/11 = -22/11 = -2 Checks
5x = 2y -9 --> -115/11 = -16/11 - 99/11 Checks