Before you learn How to Find the Value of an Algebraic Expression,
you must know:
What are Constants ?
What are Variables ?
Value of an Algebraic Expression :
By assigning values to variables in an algebraic expression, you can find the value of the expression.
From following examples you can learn How to Find The Value of an Algebraic Expression:
Example 1 = Find the value of algebraic expression (p + q + r),
if (p = 1), (q = 2) and (r = 3)
Answer = The given algebraic expression is (p + q + r)
Put the respective values of (p = 1), (q = 2) and (r = 3) in the algebraic expression, and we get:
= 1 + 2 + 3
= 6
So The Value of the Given Algebraic Expression (p + q + r) is 6.
Example 2 = Find the value of algebraic expression (7x  3y + 4),
if (x = 2) and (y = 3)
Answer = The given algebraic expression is (7x  3y + 4)
Put the respective values of (x = 2) and (y = 3)in the algebraic expression, and we get:
= (7 X 2)  (3 X 3) + 4
Solve brackets and we get
= 14  9 + 4
Solve and we get:
= 9
So The Value of the Given Algebraic Expression (7x  3y + 4) is 9.
Example 3 = Find the value of algebraic expression (8a ÷ 4b),
if (a = 2)and (b = 2)
Answer = The given algebraic expression is (8a ÷ 4b)
Put the respective values of (a = 2)and (b = 2) in the algebraic expression, and we get:
= (8 X 2) ÷ (4 X 2)
solve Brackets and we get:
= 16 ÷ 8
After division, we get:
= 2
So The Value of the Given Algebraic Expression (8a ÷ 4b) is 2.
Value of the given Algebraic expression is dependent on the value of it's variables
Or we can say that:
On the changing the value of variables, value of algebraic expression also changes.
Example : Find value of a + b + 4, if a = 2 and b = 3
Solution = The given algebraic expression is (a + b + 4)
Put the respective values of (a = 2) and (b = 3) in the given algebraic expression, and we get:
= 2 + 3 + 4
= 9
The Value of the Algebraic Expression a + b + 4 is 9, if a = 2 and b = 3....... (Statement 1)
Now lets change the value of variable i.e a = 1 and b = 5 in given algebraic expression i.e. a + b + 4. And observe the What happens ?
So here we again find the value of given algebraic expression a + b + 4 with a = 1 and b = 5
Put the respective values of (a = 1) and (b = 5) in the given algebraic expression, and we get:
= 1 + 5 + 4
= 10
The Value of the Algebraic Expression a + b + 4 is 10, if a = 1 and b = 5 ........ (Statement 2)
Hence from statement 1 and 2, you can observe that value of given algebraic expression changes when we change the values of its variable a and b.

