Answer:
<h2>A) 3 cm</h2>
Step-by-step explanation:
The formula of a volume of a cylinder:

r - radius
H - height
We have r = 1cm and H = 21cm. Substitute:

The formula of a cone:

r - radius
H - height
We have V = 21π cm³ and H = 7cm. Substitute:
<em>divide both sides by π</em>
<em>divide both sides by 7</em>
<em>multiply both sides by 3</em>

Answer:
Step-by-step explanation:
3x - 4y = 13 (1)
2x + y = 5 (2)
——————
3x - 4y = 13
4(2x + y = 5) (2) times 4
——————-
3x - 4y = 13
8x + 4y = 20
——————-
11x = 33
x = 33/11
x = 3
Plug x = 3 in (2):
2(3) + y = 5
6 + y = 5
y = 5-6
y = -1
Thus, x = 3 and y = -1
Answer:
0 = a
Step-by-step explanation:
The first thing to do is subtract 5 from both sides.
a + 5 = 5a + 5
- 5 - 5
The 5's cancel out.
Now we have a + 0 = 5a
You next subtract the a from both sides.
a + 0 = 5a
-a -a
0 = 4a
Lastly would to get a by itself so then we divide 4 from both sides
0 = 4a
_ _
4 4
0 = a
Answer: 
Step-by-step explanation:
We have the following polynomial:

This is a polynomial of the form
. Following this rule to expand it, we have:


Applying common factor
:

Note the polynomial inside the parenthesis is a perfect square trinomial, which can be factored to
. Hence, the final simplification is:

Answer:
The answer is option B.
Step-by-step explanation:

Hope this helps you