Question: What value of c will complete the square below (
) and make the expression a perfect square trinomial?
Answer: c = 225
Step-by-step explanation:
Perfect square trinomials come in the form a² + 2ab + b², which is equal to (a + b)². In the presented trinomial, we can immediately identify that <u>a = x, and b² = c</u>, but we need to find the numerical value of 
.
To do this, note that the middle term, or <u>2ab, corresponds with (is equal to) 30x</u>. We know that a = x, and thus, <u>2ab = 2bx</u>. Now, 2bx and 30x are corresponding terms; thus, <u>2bx = 30x</u>.
Dividing by 
on both sides gives us <u>b = 15</u>. Therefore, c = b² = 15² = 225. (As a squared binomial, this would be (x + 15)² as a = x and b = 15.)
X = 5, that’s the answer to question 12
Problem 2
Part (a)
The 3D shape formed when rotating around the y axis forms a pencil tip
The shape formed when rotating around the x axis is a truncated cone turned on its side.
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Part (b)
Check out the two diagrams below.
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Problem 3
Answer: Choice A and Choice C
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Explanation:
Think of stacks of coins. Let's say we had 2 stacks of 10 quarters each. The quarters are identical, so they must produce identical volumes. Those sub-volumes then add up to the same volume for each stack. Now imagine one stack is perfectly aligned and the other stack is a bit crooked. Has the volume changed for the crooked stack? No, it hasn't. We're still dealing with the same amount of coins and they yield the same volume.
For more information, check out Cavalieri's Principle.
With all that in mind, this leads us to choice C. If the bases are the same, and so are the heights, then we must be dealing with the same volumes.
On the other hand, if one base is wider (while the heights are still equal) then the wider based block is going to have more volume. This leads us to choice A.
Answer:
B
Step-by-step explanation:
Product is what you get when you multiply
Equation::
value + value = value
80x + 60(50-x) = 74*50
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80x + 60*50 - 60x = 74*50
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20x = 14*50
x = 35 lbs (amt. of 80 cent tea to use)
50-x = 15 lbs (amt. of 60 cent tean to use)
