Answer:
(2x - 3)(2x + 3)
Step-by-step explanation:
Given
4x² - 9
This is a difference of squares and factors in general as
a² - b² = (a - b)(a + b)
4x² = (2x)² ⇒ a = 2x
9 = 3² ⇒ b = 3, thus
4x² - 9 = (2x - 3)(2x + 3) ← in factored form
Answer:
12
Step-by-step explanation:
To find the mean of a set of numbers, add all the numbers together. Then, divide the sum by how many numbers you had to begin with.
Add the numbers together:
10 + 12 + 15 + 11
= 48 This is the sum of the data
Count how many numbers you had:
10, 12, 15 and 11 are FOUR numbers (amount of data).
Divide the sum of the data by the amount of data.
48 ÷ 4 = 12 This is the mean
The mean of 10, 12, 15, 11 is 12.
Expanded form pretty much means that you break down every digit into an addition phrase. So, for 418,832, that would mean:
4 1 8 8 3 2
400000 10000 8000 800 30 2
400000+10000+8000+800+30+2