What's the question being asked here?
Answer:
1 .4x2-9= 2x+3,2x-3
2 .16x2-1=4x-1,4x+1
3 .16x2-4=4(2x+1)(2x-1)
4 .4x2-1=(2x+1)(2x-1)
Step-by-step explanation:
16x² − 1 = (4x − 1)(4x + 1) ; 16x² − 4 = 4(2x + 1)(2x − 1); 4x² − 1 = (2x + 1)(2x − 1) ;
4x² − 9 = (2x + 3)(2x − 3)
16x² − 1 is the difference of squares. This is because 16x² is a perfect square, as is 1. To find the factors of the difference of squares, take the square root of each square; one factor will be the sum of these and the other will be the difference.
The square root of 16x² is 4x and the square root of 1 is 1; this gives us (4x-1)(4x+1).
16x² − 4 is also the difference of squares. The difference of 16x² is 4x and the square root of 4 is 2; this gives us (4x-2)(4x+2). However, we can also factor a 2 out of each of these binomials; this gives us
2(2x-1)(2)(2x+1) = 2(2)(2x-1)(2x+1) = 4(2x-1)(2x+1)
4x² − 1 is also the difference of squares. The square root of 4x² is 2x and the square root of 1 is 1; this gives us (2x-1)(2x+1).
4x² − 9 is also the difference of squares. The square root of 4x² is 2x and the square root of 9 is 3; this gives us (2x-3)(2x+3).
Answer:
$1800
Step-by-step explanation:
Volume of the foundation: 30*12*6 = 2160 cubic feet
we need to convert this into yards because a truckload is 8 cubic yards, 2160/3 = 720 cubic yd
One truckload is 8 cubic yards
# of truckloads needed: 720/8 = 90 truckloads
Cost: $20*90 = $1800
Answer: 6
Step-by-step explanation:
Answer:
A sample of 1068 is needed.
Step-by-step explanation:
In a sample with a number n of people surveyed with a probability of a success of 
, and a confidence level of 
, we have the following confidence interval of proportions.
In which
z is the zscore that has a pvalue of 
.
The margin of error is:
95% confidence level
So 
, z is the value of Z that has a pvalue of 
, so 
.
At 95% confidence, how large a sample should be taken to obtain a margin of error of 0.03 for the estimation of a population proportion?
We need a sample of n.
n is found when M = 0.03.
We have no prior estimate of , so we use the worst case scenario, which is 
Then
Rounding up
A sample of 1068 is needed.
