+0  
 
0
128
1
avatar

3x+3y=9

5x-8y=-9

Guest May 7, 2017

Best Answer 

 #1
avatar+4786 
+4

3x + 3y = 9

5x - 8y = -9

 

Multiply the top equation through by -5/3.

3(-5/3)x + 3(-5/3)y = 9(-5/3)

-5x - 5y = -15

 

Now line this up with the second equation and add straight down.

   -5x - 5y   = -15

+  5x - 8y   = -9

    0x - 13y = -24

 

-13y = -24

y = -24/-13

y = 24/13

 

Now substitute this value for y into either equation to find x.

3x + 3(24/13) = 9

3x = 9 - 72/13

3x = 45/13

x = 15/13

hectictar  May 7, 2017
Sort: 

1+0 Answers

 #1
avatar+4786 
+4
Best Answer

3x + 3y = 9

5x - 8y = -9

 

Multiply the top equation through by -5/3.

3(-5/3)x + 3(-5/3)y = 9(-5/3)

-5x - 5y = -15

 

Now line this up with the second equation and add straight down.

   -5x - 5y   = -15

+  5x - 8y   = -9

    0x - 13y = -24

 

-13y = -24

y = -24/-13

y = 24/13

 

Now substitute this value for y into either equation to find x.

3x + 3(24/13) = 9

3x = 9 - 72/13

3x = 45/13

x = 15/13

hectictar  May 7, 2017

19 Online Users

avatar
avatar
avatar
avatar
We use cookies to personalise content and ads, to provide social media features and to analyse our traffic. We also share information about your use of our site with our social media, advertising and analytics partners.  See details