Expression A and expression B are written on cards; cards of the same colour hold like terms. What is A + B?

Class 8Algebraic Expressions and IdentitiesAlgebra

Step-by-Step Solution

Add like terms:

4 a^{2} - a^{2} = 3 a^{2}, - 3 ab + 5 ab = 2 ab, 7 - 2 = 5

. The term

2 b

has no like term, so

A + B = 3 a^{2} + 2 ab + 2 b + 5

Answer: B)

3 a^{2} + 2 ab + 2 b + 5

Combine **like terms only** — same variables and same powers.

Example:

(3 x^{2} + 4 x - 2) + (5 x^{2} - 7 x + 8) = (3 x^{2} + 5 x^{2}) + (4 x - 7 x) + (- 2 + 8) = 8 x^{2} - 3 x + 6

.

For subtraction, distribute the minus sign first:

(3 x^{2} + 4 x) - (x^{2} - 2 x) = 3 x^{2} + 4 x - x^{2} + 2 x = 2 x^{2} + 6 x

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