Question

0.2x-0.3y=4 , 2.3x-y=1.2 by substuition method

Answer 1

Given:

Equations,

                               $0.2x - 0.3y = 4\\ 2.3x-y = 1.2$

To Find:

$x$ and $y$

Solution:

In the Substitution method, we have to write the equation in terms of one of the two variables and then put the value to the other equation.

By Substitution Method:

Suppose,

$0.2x - 0.3y = 4 ----------> eq(1)\\ 2.3x-y = 1.2-----------> eq(2)$  

Taking equation (2), we have  

$2.3x-y = 1.2$  

$y=2.3x-1.2------->eq(3)$  

Putting $y=2.3x-1.2$ in equation (1), we get  

$0.2x-0.3y = 4$  

$0.2x-0.3(2.3x-1.2)=4$  

$0.2x-0.69x+0.36=4$  

$0.49x+0.36 =4$  

$-0.49x=4-0.36\\ -0.49x=3.64\\x=\frac{-3.64}{0.49}$    

Now, Putting $x=\frac{-3.64}{0.49}$ in equation (3), we get

$y=2.3x-1.2\\y=2.3(\frac{-3.640}{0.49})-1.2$    

$y=\frac{-8.372-0.5880}{0.49} \\y=\frac{-8.960}{0.49} \\y=-18.285$

The value of x = -7.42 and y = -18.28.