Question

.simplify
(2a+5)²-(a+3)(a-3)​

Answer 1

Answer: 3a² + 20a + 34

Concept:

When doing simplifying expressions, following the PEMDAS method would be easier.

• Parentheses
• Exponents
• Multiplication
• Division
• Addition
• Subtraction

When expanding parentheses, following the FOIL method would be easier.

• First
• Outer
• Inner Last

Solve:

Given expression

(2a + 5)² - (a + 3) (a - 3)

Simplify exponenets

= (2a + 5) (2a + 5) - (a + 3) (a - 3)

Expand parentheses

= 4a² + 10a + 10a + 25 - (a² - 3a + 3a - 9)

= 4a² + 10a + 10a + 25 - a² + 3a - 3a + 9

Combine like terms

= 4a² - a² + 10a + 10a + 3a - 3a + 25 + 9

= 3a² + 20a + 34

Hope this helps!! :)

Please let me know if you have any questions

Answer 2

3a^2 + 20a + 34

Explanation:

(2a + 5)^2 = 4a^2 + 20a + 25

(a +3)(a - 3) = a^2 - 9

Put these two partial answers together.

4a^2 + 20a + 25 -(a^2 -9 ) Remove the brackets.

4a^2 + 20a + 25 - a^2 + 9

4a^2 + 20a + 25 - a^2 + 9

3a^2 + 20a + 34