Answer:
The second choice is the correct one.
Step-by-step explanation:
20x^4 - 45x^2
GCF is 5x^2, so the factors are:
5x^2( 4x^2 - 9)
Now 4x^2 - 9 is the differencr of 2 squares:
4x^2 - 9 = (2x + 3)(2x - 3)>
In order to not get confused, start by converting cm to m
h=20 cm = 0.2m and r=5cm = 0.05m
The cans are cylinders and we only need the rectangular shape, which is equal to the height x the circumference of the circle (2r(pi)), which you'll have to multiply by 200,000 for the number of cans necessary
your equation is therefore:
A=200,000h(2pi(r))
A=200,000(0.2)(2)(0.05)(pi)
A=4000pi m^2
If you're factoring, your answer is
(4x - 3)(4x + 5)
You'll work it out this way:
16x^2 + 8x - 15
Since there's no GCF here, you multiply the first and third terms, giving you -240. Your next step is to find two numbers that have a sum of 8 and a product of -240. These numbers are 20 and -12. Plug those in and you've got:
16x^2 + 20x - 12x - 15
From here you divide it into two binomials. These are (16x^2 + 20x) and (-12x - 15).
When you take out the greatest common factors (4x and -3), they become:
4x(4x + 5) - 3(4x + 5)
Then you group what's outside of the parentheses together (4x - 3)
And bring what's inside of the parentheses down (4x + 5).
This brings your answer to
(4x - 3)(4x + 5)
14 = 9 - x
First, subtract 9 from both sides.
14 - 9 = (9 - 9) - x
5 = -x
Now divide both sides by -1.
5/-1 = -1/-1x
-5 = x
The answer is x = -5.
