For example,
Q1) Find x if 8x + 12 = 60.
It is given that 8x+12=60.
We can take away 12 from both sides,
Therefore, 8x=60-12=48.
If 8 pens were to cost $48, you knoe the cost of each is 48/8=6.
Similarly, here x=6 since 8x=48.
Q2. If 3x + 2y = 16 and 2x-y=1, find x and y.
(These are called simultaneous equations of two variables)
Lets take 3x + 2y = 16 as equation (1)
and 2x - y = 1 as equation (2).
We have to first eliminate one variable, that is either x or y.
In order to do that, we have to make x or y equal in both the equations. Lets eleminate y here.
3x + 2y = 16 ... equation (1)
equation (2) x 2 : 4x - 2y = 2
Adding equations (1) and (2)
3x+4x +2y+-2y = 16-2.
7x = 14,
x=2.
Now put x=2 in equation(1)
3x + 2y = 16
3(2) + 2y = 16
6 + 2y = 16
2y = 16-6 = 10.
Therefore, y = 10/2 = 5.
Therefore, the solution is x=2, y=5.