Question

Solve the following system of equations by using the substitution method.

Answer 1

Solution :

Given equations, $x-y=3\\2x+2y=2$

Applying Substitution method to solve the equation.

Solve the first equation $x-y=3$ for x,

$x-y=3\:\Rightarrow x=3+y$

Substitute the value of x in second equation,

$2x+2y=2\\\\\Rightarrow 2(3+y)+2y=2\\\\\Rightarrow 6+2y+2y=2\\\\\Rightarrow6+4y=2\\\\\Rightarrow4y=2-6\\\\\Rightarrow4y=-4\\\\\Rightarrow y=\frac{-4}{4} =-1\\\\\Rigtharrow y=-1$

To calculate the value of  x  substitute the value of y in first equation

$x-y=3\\\\\Rightarrow x-(-1)=3\\\\\Rightarrow x=3-1=2\\\\\Rightarrow x=2$

Hence, the solution of the equations $x-y=3\\2x+2y=2$ is (2,-1).

Answer 2

3,4 would be the answer