We can solve linear equations consisting of 2 variables by taking value of one variable from one of the equation and putting into the other.
Let’s take an example. We have equations:
(1)
(2)
Using equation (1), we can write value of variable x in the form of variable y.
(3)
In the second step, we just need to put equation (3) in the (2) equation. It will give us the value of variable y.
So, putting (3) in equation (2), we get
Subtracting 5 from both sides, we get
Dividing both the sides by -2, we get
(We get value of one variable at this point.)
To get value of x, we just need to put value of y in (1), (2) or (3) equation.
So, putting value of y in equation (1), we get
Therefore,
and
(This is the solution.)
Let’s solve one more problem. We have equations:
(1)
(2)
Using equation (2), we can write value of variable x in the form of variable y.
(3)
Putting (3) in equation (1), we get
Putting value of y in equation (1), we get
Therefore,
and
( This is the solution.)
In the first step, we can also write value of variable y in the form of variable x.
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