Answer:
5
Step-by-step explanation:
n + m -2(m-m)
Combine like terms
n+m+2(0)
n+m
Let m=3 and n=2
2+3
5
Answer:

Step-by-step explanation:
Let height of a banner be
, then we know that this is
of the length
of the banner; so we have
.
Now we can rearrange this equation to solve for the length of the banner given it's height:

So there we have it!
If the banner is 5 ft tall, then it's length will be:

Answer:
13
Step-by-step explanation:
y=mx+b
b= y-intercept
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