Arectangular block is such that the sides of its base are of the length x cm and 3x cm. the sum of all the lengths of all its edges is 20cm. find the volume.

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

center (1,3) with radius 6

step-by-step explanation:

we must complete the square to find the center and radius of the circle.

first make sure the x and y squared terms have 1 as their coefficients. we also make sure x and y terms together.

we now create space between the x and y terms with parenthesis.

we complete the square by taking the middle terms -2x and the -6y - divide each and square them.

we add the squares to both sides.

simplify.

and write the quadratics in factored form.

the center is (h,k) or (1,3). the radius is the square root of 36 which is 6.

1. 2

2. 11

3. 5

4. 6

5. 7

6. 5

7. -1

8. 1

step-by-step explanation: