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trasher [3.6K]
3 years ago
6

a 15-ft ladder is leaning against one wall of an alley 9 ft wide. the ladder slips, its top sliding down the wall, its foot slid

ing across the alley and striking the opposite wall at a speed of 4 ft/sec. How fast is the top of the ladder falling at that instance?
Mathematics
1 answer:
blagie [28]3 years ago
5 0
2x dx/dt +2y dy/dt = 0 
<span>x dx/dt + y dy/dt = 0 </span>
<span>9*4 + 12 dy/dt = 0 </span>
<span>dy/dt = - 3 ft/sec </span>
You might be interested in
How is the quotient 5 to the 8th power expressed as a power of 5
Sauron [17]

Answer:

5^4

Step-by-step explanation:

When dividing exponents with the same base, you subtract their exponents.

8-4=4

This means that 5^8 / 5^4 is equal to:

5^4

6 0
3 years ago
A shirt originally cost $54.01, but it is on sale for $37.81. What is the percentage decrease of the price of the shirt? If nece
Marianna [84]

I think it's rounds at to 30

3 0
3 years ago
Please help!!!!!!!!!!
Sergeu [11.5K]
1, 3, and 5 would be my best guesses but I’m not 100 percent sure
7 0
3 years ago
The half-life of lead is 22 years. How long will it take for a sample of this substance t decay to 80% of its original amount?
Svetlanka [38]

Answer: 7 years

Step-by-step explanation:

t_{\frac{1}{2} } = In2 / ∧

since the half life is given , we have :

22 = In 2/ ∧

∧ = In2/22

∧ = 0.032

Recall the formula for half life:

\frac{N(t)}{N(0)} = e^{-∧t}

Therefore:

0.80 = e^{-0.032t}

Take the In of both sides

In 0.80 = - 0.032t

t = In 0.80 / - 0.032

t = 7 years

4 0
3 years ago
For each value of U, determine whether it is a solution,
abruzzese [7]
Given u/7 - 1 = 7 and plugging in values for u,

For u = 28; 28/7 - 1 = 4 - 1 = 3; No
For u = -49; -49/7 - 1 = -7 - 1 = -8; No
For u = 42; 42/7 - 1 = 6 - 1 = 5; No
For u = 0; 0/7 - 1 = -1; No

Another way to find out which value would be a solution to u/7 - 1 = 7 is to solve for u.

u/7 - 1 = 7
u/7 = 7 + 1
u/7 = 8
u = 8*7
u = 56

The only solution to this equation is when u = 56.
8 0
3 years ago
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