Answer:
15x^2 - 12x^3
Step-by-step explanation:
A rectangular block has 3 parts that play into its volume. length, width and height. The question gives us length and width in the form of x and 3x, so height is what's missing.
It gives us a bit more information saying the sum of its edges is 20. We also have to ask how many lengths, widths and heights are there. That may be a bit hard to understand, but is you are looking at a block I could ask how many edges are vertical, just going up and down. These would be the heights. There are 4 total, and this goes the same for length and width, so 4*length + 4*width and 4*height = 20.
Taking that and plugging in x for length and 3x for width (or you could do it the other way around, it doesn't matter, you get:
4*x + 4*3x + 4*height = 20
4x + 12x + 4h = 20
16x + 4h = 20
4h = 20 - 16x
h = 5 - 4x
Now we have h in terms of x, which lets us easily find the volume just knowing x. To find the volume of a rectangular block you just multiply the length, width and height.
x*3x*(5-4x)
3x^2(5-4x)
15x^2 - 12x^3
Question doesn't give a specific value for x at all so you should be done there. Any number you plug in for x should get you the right answer
<span>Turn 1 3/4 into a decimal number: 1.75
So, 120 miles in 1.75 hours, but we want to know miles in *one* hour. Divide both numbers by 1.75. 120/1.75 miles in 1.75/1.75 hour = 120/1.75 miles in 1 hour. 120/1.75 is 68.57 miles in one hour, so 68.57 mph.</span>
Answer: x = 17/9
Step-by-step explanation: Lets solve for x.
9x - 5 = 12
9x - 5 + 5 = 12 + 5
9x = 17
9x/9 = 17/9
x = 17/9
Answer:
≈ 56°
Step-by-step explanation:
Using the sine ratio in the right triangle
sin ? =
=
, then
? =
(
) ≈ 56° ( to the nearest degree )
Answer: a
Step-by-step explanation: