+0  
 
0
212
1
avatar

1. 8a-3b=-4 

    a=5-2b

 

 

2. 2x-3y=1

    x=y+1

 

 

3. 2x+y=5

    x-3y=13

Guest Mar 2, 2017
 #1
avatar+92806 
0

1. 8a-3b=-4 

    a=5-2b

 

You know that a equals 5-2x so put this in brackedts and sub it into your first equation.


\(8a-3b=-4 \qquad (1)\\  a=(5-2b)\qquad (2)\\~\\ 8(5-2b)-3b=-4 \\ \text{now solve it for b}\\ 40-16b-3b=-4\\ 40-19b=-4\\ 40-19b-40=-4-40\\ 19b=-44\\ b=\frac{-44}{19}\\ b=-2\frac{6}{19}\\~\\ \text{Now sub this value of b into (2)}\\ a=5-2*\frac{-44}{19}\\ a=5+\frac{88}{19}\\ a=5+4\frac{12}{88}\\ a=9\frac{3}{22}\\ so\\ b=-2\frac{6}{19}\qquad and \qquad a=9\frac{3}{22}\\ \)

 

You can do ther others by copying this one. :)

Melody  Mar 2, 2017

6 Online Users

New Privacy Policy

We use cookies to personalise content and advertisements and to analyse access to our website. Furthermore, our partners for online advertising receive information about your use of our website.
For more information: our cookie policy and privacy policy.