What's one in 25?

What's one in 25?

1/25=1/20-1/100
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Solving the equation 7 ^ x-3 * 2 ^ y = 1

（1,1）,（2,4）
Obviously, (1,1), (2,4) are the solutions of the equation
It is shown that when y ≥ 5, the equation has no solution
Suppose y ≥ 5,
Then 7 ^ x-3 * 2 ^ y ≡ 7 ^ x-3 * 32 * 2 ^ (Y-5)
≡7^x≡1 （mod 32）
∵ 7 ^ 4 ≡ 1 (MOD 32) (Euler theorem)
∴4|x
7 ^ 4 ≡ 1 (Mod 5)
∴7^x-3*2^y≡1-2^（y-1）≡1 （mod 5）
Then 2 ^ (Y-1) ≡ 0 (Mod 5)
contradiction
The hypothesis does not hold
The solution of the original equation (1,1), (2,4)

What are cos0 degree 90 degree 180 degree, sin0 degree 90 degree 180 degree? There is a method of image understanding

1 0 -1
0 1 0

How to solve the equation x / 36 + X / 24 = 15?

x/36+x/24=15
The two sides are multiplied by the least common multiple 72 of the denominator to obtain:
2x+3x=1080
5x=1080
x=1080÷5
x=216

A story book has 640 pages. Xiaojun read two fifths of the whole book in four days. How many days does Xiaojun finish reading this book?
Use the formula

4/（2/5）=10

9. As shown in the figure, place a rectangular trapezoid AOCD in the plane rectangular coordinate system. It is known that ad = 3, Ao = 8, OC = 5, if point P is in the trapezoid
9. As shown in the figure, place a right angle trapezoid AOCD in the plane rectangular coordinate system. It is known that ad = 3, Ao = 8, OC = 5. If point P is in the trapezoid and s △ pad = s △ POC, s △ Pao = s △ PCD, then the coordinate of point P is

Let P (x, y) then
1/2 X3X(8 - y)=1/2 X5y ;
1/2 X8x＋1/2 X5y=1/2 X[1/2X(3+5)X8]
The solution is x = 17 / 8; y = 3
P coordinate is (17 / 8,3)

The quotient of a number and one in five equals 30 percent of 60. Find this number

Let this number be X
 
X △ 1 / 5 = 60 × 30%
 
5x=18
 
x=18÷5
 
X = 18 / 5
 

The equation x square / (M + 1) + y square / (2-m) = 1, which represents the ellipse with focus on Y axis and the value range of M

Ellipse with focus on Y axis
Then 0

If f (SiNx) = cos (x), then f (cosx)

If f (SiNx) = cos (x), then f (cosx)
Let t = SiNx (- 1 ≤ t ≤ 1)
cosx=±√1-sinx²=±√1-t²
f(t)=±√1-t²
∴f(cosx)=±√1-cosx²=±sinx

Given that the line y = - 4-2x intersects with the line y = 3x + B in the third quadrant, then the value range of B is ()
A. B ＞ - 4B. B ＜ 6C. - 4 ＜ B ＜ 6D. B is any real number

The analytic formula of two simultaneous straight lines is: y = - 4 − 2XY = 3x + B, the solution is x = - B + 45y = 2B − 125; because the intersection coordinates of the two straight lines are in the third quadrant, the solution is - 4 ＜ B ＜ 6; so choose C