Question

Explain how to simplify this expression: (7a+ 9) + (4a – 7) in words.

Answer 1

Think of the letter 'a' to represent 1 apple.

a = 1a = 1 apple

2a = 2 apples

3a = 3 apples

and so on

Adding 7a with 4a means we have 7 apples and we add on 4 more. We'll have 7+4 = 11 apples total.

Algebraically we write 7a+4a = 11a to do this using shorthand.

The 9-7 portion is calculated like you'd expect and it simplifies to 2.

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Here's what the step by step picture looks like

(7a+9) + (4a-7)

7a + 9 + 4a - 7

(7a+4a) + (9-7)

11a + 2