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For example: The statement x – 3 is greater than 10, i.e., x – 3 > 10 is not Remember
an equation. If the LHS is not equal to

Similarly, the statement x – 3 is smaller than 10 i.e., x – 3 < 10 is also the RHS, we do not get an
not an equation. equation.
Example 1: Identify the equations in the following mathematical statements. In case of equations
with a variable, identify the variable.

1
(a) x + 2 = 11 (b) 2y – 1 > 5 (c) 7 – p < 2 (d) 2 m = 3
t 2n a + 2
(e) < 1 (f) −> (g) = 1
51
3 3 3
Solution: (a) x + 2 = 11 Yes, variable: x

(b) 2y – 1 > 5 No FACTS
An equation remains the same
(c) 7 – p < 2 No when the expressions on the
1 LHS and RHS are interchanged.
(d) 2m = Yes, variable: m As 3x + 5 = 2x + 1 is same as
3
t 2x + 1 = 3x + 5.
(e) < 1 No
3
2n
(f) −> No
51
3 Maths Talk
a + 2 Does 3 × 5 = 15 represent an
(g) = 1 Yes, variable: a equation. If not, then why? Discuss.
3
Example 2: Write the LHS and RHS of the following equations:
(a) x + 3 = 7 (b) 3 – 4x = 15 (c) 9x – 3 = 7x + 4 (d) 4x + 7 = 2x

Solution: (a) LHS = x + 3 and RHS = 7 (b) LHS = 3 – 4x and RHS= 15
(c) LHS = 9x – 3 and RHS = 7x + 4 (d) LHS = 4x + 7 and RHS = 2x
Example 3: Write the simple equation for the following statements:

(a) The sum of double of number x and 5 is 23.
(b) 7 subtracted from three times of m is 15.
(c) Twice of the number x divided by 7 gives 6.
(d) 6 is subtracted from the product of 4 and y is 60.

(e) 3 added to one-third of a gives 30.
Solution: (a) The sum of double of number x and 5 is 2x + 5. And the sum is 23. Therefore, the
equation is 2x + 5 = 23.

(b) 7 subtracted from three times of m is 3m – 7. The difference is 15. Therefore, the
equation is 3m – 7 = 15.

(c) Twice of number x is 2x. When 2x is divided by 7 we get. It gives 6. Therefore, the
2x
equation is = 6 .
7

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