For solving system of equations, we can use either substitution where we plug one equation into the other, or elimination where we combine the equations.
- Using elimination, you would to eliminate one variable from both equations, so you automatically would get one equation with one variable!
- Using substitution means you are going to solve one equation for one variable and substitute with its value in the other equation in order to get also an equation with one variable.
Let's take an example ...
y+x=2 and y-2x = 1
Using elimination, we need to subtract these two equation; one from the other...
y+x=2
-
y-2x=1
-----------
0+3x=1
then x=1/3
and then substitute into any equation to get y-value
y+x=2
y+1/3 = 2 >>>>> y=5/3
NOW...Using substitution
y+x=2 and y-2x = 1 >>(y=1+2x)
Plug (y=1+2x) into y+x=2 and solve for x
y+x=2
(1+2x) + x =2
1+3x = 2
3x=1
again (and for sure) x = 1/3
plug in x=1/3 into any of the equations above to get y:
y+x=2
y+1/3=2
y=5/3
DOne !!!!!!
I hope you got the idea If you still need help, just let me know.