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Dmitry_Shevchenko [17]

2 years ago

10

A ladder is placed against a wall such that the top is 8 feet above the ground. If the ladder is 10 feet long, how far away from

the wall is the base of the ladder

1 answer:

Annette [7]2 years ago

7 0

Answer:

6 feet

Step-by-step explanation:

Consider the right triangle formed by the wall, ladder and ground.

Let the distance the ladder is from the wall be d , then

Using Pythagoras' identity in the right triangle

The square on the hypotenuse ( ladder) is equal to the sum of the squares on the other 2 sides ( wall and d ), then

d² + 8² = 10²

d² + 64 = 100 ( subtract 64 from both sides )

d² = 36 ( take the square root of both sides )

d = $\sqrt{36}$ = 6

That is the ladder is 6 feet away from the wall

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The highest point in colorado is mount elbert, at 14,433 feet.About how many miles is that

Juli2301 [7.4K]

2.7335227 because you know how ,any ft. are in 1 mile so you just multiply :)

8 0

2 years ago

Solve the following equations: (a) x^11=13 mod 35 (b) x^5=3 mod 64

tino4ka555 [31]

a.

$x^{11}=13\pmod{35}\implies\begin{cases}x^{11}\equiv13\equiv3\pmod5\\x^{11}\equiv13\equiv6\pmod7\end{cases}$

By Fermat's little theorem, we have

$x^{11}\equiv (x^5)^2x\equiv x^3\equiv3\pmod5$

$x^{11}\equiv x^7x^4\equiv x^5\equiv6\pmod 7$

5 and 7 are both prime, so $\varphi(5)=4$ and $\varphi(7)=6$ . By Euler's theorem, we get

$x^4\equiv1\pmod5\implies x\equiv3^{-1}\equiv2\pmod5$

$x^6\equiv1\pmod7\impleis x\equiv6^{-1}\equiv6\pmod7$

Now we can use the Chinese remainder theorem to solve for $x$ . Start with

$x=2\cdot7+5\cdot6$

Taken mod 5, the second term vanishes and $14\equiv4\pmod5$ . Multiply by the inverse of 4 mod 5 (4), then by 2.

$x=2\cdot7\cdot4\cdot2+5\cdot6$

Taken mod 7, the first term vanishes and $30\equiv2\pmod7$ . Multiply by the inverse of 2 mod 7 (4), then by 6.

$x=2\cdot7\cdot4\cdot2+5\cdot6\cdot4\cdot6$

$\implies x\equiv832\pmod{5\cdot7}\implies\boxed{x\equiv27\pmod{35}}$

b.

$x^5\equiv3\pmod{64}$

We have $\varphi(64)=32$ , so by Euler's theorem,

$x^{32}\equiv1\pmod{64}$

Now, raising both sides of the original congruence to the power of 6 gives

$x^{30}\equiv3^6\equiv729\equiv25\pmod{64}$

Then multiplying both sides by $x^2$ gives

$x^{32}\equiv25x^2\equiv1\pmod{64}$

so that $x^2$ is the inverse of 25 mod 64. To find this inverse, solve for $y$ in $25y\equiv1\pmod{64}$ . Using the Euclidean algorithm, we have

64 = 2*25 + 14

25 = 1*14 + 11

14 = 1*11 + 3

11 = 3*3 + 2

3 = 1*2 + 1

=> 1 = 9*64 - 23*25

so that $(-23)\cdot25\equiv1\pmod{64}\implies y=25^{-1}\equiv-23\equiv41\pmod{64}$ .

So we know

$25x^2\equiv1\pmod{64}\implies x^2\equiv41\pmod{64}$

Squaring both sides of this gives

$x^4\equiv1681\equiv17\pmod{64}$

and multiplying both sides by $x$ tells us

$x^5\equiv17x\equiv3\pmod{64}$

Use the Euclidean algorithm to solve for $x$ .

64 = 3*17 + 13

17 = 1*13 + 4

13 = 3*4 + 1

=> 1 = 4*64 - 15*17

so that $(-15)\cdot17\equiv1\pmod{64}\implies17^{-1}\equiv-15\equiv49\pmod{64}$ , and so $x\equiv147\pmod{64}\implies\boxed{x\equiv19\pmod{64}}$

5 0

2 years ago

Hi guys can you please help me with this test.

Anika [276]

Sure! but unfortunately the picture is blank. not sure if it’s just my screen

4 0

2 years ago

PLS HURRY!!!!! 40 POINTS!!!!

grigory [225]

Answer:

2+x

Step-by-step explanation:

2(1-x)=2-2x

2-2x+3x=2+x

6 0

2 years ago

Read 2 more answers

djverab [1.8K]

Answer:

x=7

Step-by-step explanation:

Find slope first

$m-\frac{y2-y1}{x2-x1}$

$m=\frac{6-5}{7-7}$

$m=\frac{1}{0}\\$

m is undefined- so it is a vertical line

x=7

6 0

2 years ago