Answer:
(2x-9)(2x+9)
Step-by-step explanation:
This is a difference of squares because it can be written as (2x)^2-9^2
The formula for factoring a difference of squares is a^2-b^2=(a-b)(a+b)
So replace a with 2x and b with 9 giving us
4x^2-81=(2x-9)(2x+9)
multiplying both sides by x^2
simplifying
dividing by 7
Answer:
16:12 or 4:3
Step-by-step explanation:
Girls + boys = 28
Girls + 12 = 28
Girls = 16
Girls to boys:
16:12
16/12
4:3
Answer:
6. 4
7. 40
8. 10
9. 4
10. 21
Step-by-step explanation:
Answer:
9
Step-by-step explanation:
sum of the terms
mean=------------------------------
number of the terms
