a.
By Fermat's little theorem, we have
5 and 7 are both prime, so and . By Euler's theorem, we get
Now we can use the Chinese remainder theorem to solve for . Start with
- Taken mod 5, the second term vanishes and . Multiply by the inverse of 4 mod 5 (4), then by 2.
- Taken mod 7, the first term vanishes and . Multiply by the inverse of 2 mod 7 (4), then by 6.
b.
We have , so by Euler's theorem,
Now, raising both sides of the original congruence to the power of 6 gives
Then multiplying both sides by gives
so that is the inverse of 25 mod 64. To find this inverse, solve for in . 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 .
So we know
Squaring both sides of this gives
and multiplying both sides by tells us
Use the Euclidean algorithm to solve for .
64 = 3*17 + 13
17 = 1*13 + 4
13 = 3*4 + 1
=> 1 = 4*64 - 15*17
so that , and so
first subtract the last equation from the first. this gives:-
-x + y = -8 .....................(1)
Then multiply the first equation by 2 and add it to the 2nd equations This gives
9x = 18
so x = 2
and from equation (1) y = -8 + 2 = -6
Substituting for x and y in the second equation
z = (24 -5(2) -12) / 2 = 1
Answer is choice b.
Answer:
The measure of the side is 8.8.
Step-by-step explanation:
Since , then , , and . From figure we have the following relationship:
(1)
Where is the proportionality ratio.
If we know that , then the measure of side is:
(1b)
(1c)
The measure of the side is 8.8.