It takes some trial and error
To find the factored form, you know that the format will look like
(x^n +/- a) (x^n +/- b)
Since the expanded form has x^4, the first part of each expression in parentheses will be x^2 because x^2 * x^2 will give you x^4
Then you have to figure out, how will you get -9 in the expanded form? The "a" and "b" parts of each expression will have to multiply to equal -9.
Factors of -9 will be -3*3 or -1*9 or -9*1
Also, consider the 8x^2 part - as it relates to finding the factors of 9. The parts of the expression that result in 8x^2 in the expanded form ...
a*x^2 + b*x^2 = 8x^2
If you think about this, you know the a and b will = -1 and 9 because you also have to add the expressions with x^2 to get 8x^2, and 3 and 3 would not give you the 8x^2 and neither would nor would -9 and 1.
Final factored form is
(x^2 - 1) (x^2 + 9)
1st problem:
Use the Pythagorean theorem:
a^2+b^2=c^2
49+361=c^2
c^2=410
c=20.24
The answer is 20m
2nd problem:
First calculate the height using the Pythagorean theorem:
a^2+b^2=c^2
20^2+b^2=625 (i got 20 {radius} by half-ing the base edge length)
400+b^2=625
b^2=225
b=15
Next, solve for the volume:
V=a^2*h/3
V=40^2*15/3
V=1600*5
V=8000
The answer is the second choice or B.
4.
cos(120) = -0.87
sin(210) = -0.5
last answer
5.
sin(120) = 0.866 = sqrt3/2
1st answer
0 because no square numbers end in 8 none no matter how many digits it has.
12.95/3 = 4.32 per pound. . . . 21.45/5 = 4.29 per pound. . . . The first one is better, because too much candy is not good for you, and the slightly-higher price might convince you to buy less.
