Introduction To Unknown
Try to solve the missing number question given below. Since the numbers are easy, we can guess them right
Answer : 6 − 2 = 4.
But in algebra we use an alphabet. Therefore we can rewrite the above equation as
Since we do not know the value of the variable until it is solved, it is called the unknown or the variable.
And when we solve it we write:
Demonstration:
Solve this one:
Let us subtract 5 from both sides:
x + 5 −5 = 12 −5
(5−5 = 0 and 12−5 = 7)
Therefore, x + 0 = 7
i.e., x = 7