Question

Which among the following expressions is a constant?

• A. x+1
• B. a+b
• C. 2j
• D. 55 + 2

Answer 1

The correct option is D 55 + 2

An entity which varies or changes its value or is not consistent is called a variable.
An entity which remains fixed or unchanged is called a constant.
In the expression 'x+1', x is a variable. Since x can take any value, the value of the expression is not fixed. Hence this is not a constant.
Similarly, 'a+b' and '2j' are not constants.
But 55+2 equals 57 and its value is fixed. Therefore, this expression represents a constant.