Math Problems Urgent Math Problems Urgent

Solution: Let the single digit be x, then the ten-digit number is (x 2), and this number is 10*(x-2)+x

According to the problem: 2*[10*(x-2)+x]-17=10*x+(x-2) solution x=5

So the ten-digit number x-2=3

So this number is 35

Let the single digit be x, then the number ten is x+2, so:

10x+(x+2)]*2-17=10(x+2)+x

x=3, so the original two-digit digits: 10+3+3+2=35

Solution: If the single digit is x, then the ten digit is x-2

10x+(x-2)+17=[(x-2)*10+x]*2

The number x=5 is: (5-2)*10+5=35

Single digit x, ten digit y

The first equation: x-y=2

The second equation: 2(10x+y)-(10y+x)=17 is enough to solve the binary one-dimensional equation.

Solve the system of equations according to the meaning of the problem by assuming that the single digit is x and the ten digit is y.

x=y+210x+y=(10y+x)*2-17 The solution yields y=3 x=5

then the original number is 35

35 up! Let the single digit be a and the ten digit be b, then the value of the two-digit number is a+b*10, and the value of the new number is a*10+b

Solve a system of binary linear equations.

a-b=2a+b*10)*2-17=b+a*10. a=5

b=3yes!!

(2 + 1) (2 squared + 1) = 2 to the 4th power - 1

2 to the 4th power - 1) (2 to the 4th power + 1) = 2 to the 8th power - 1

2 to the 8th power - 1) (2 to the 8th power + 1) = 2 to the 16th power - 1

(2+1) (2 to the power of 2 + 1)) (2 to the power of 4 + 1) (2 to the power of 8 + 1) = 3x5x17x257 = 65535

A: The total cost is 200 with oil (100 A + 100 B) Average ** x A = 200 (100 A + 100 B) = 2 AB (A + B).

B: The total cost is (40a+40b) with oil 80 average ** x B = (40a + 40b) 80 = (a + b) 2x A - x B = 2ab (a + b) - (a + b) 2 = - (a - b) 2 2 (a + b).

(a-b) 2 0 , 2(a+b) 0 x A—x B 0

x A x B.

x1=200/[100/a+100/b]=2ab/(a+b)x2=[40a+40b]/80=(a+b)/2x1-x2=2ab/(a+b)-(a+b)/2=[-a-b)^2]/[2(a+b)]≤0

x1 x2x1 Average**.

x2 has averaged**.

Obviously, A is more affordable.

Test Center: Use frequency to estimate probability

Analysis: (1) Calculate according to the frequency definition of probability (2) There are m balls in the bag, and the total number of balls can be found according to the probability of touching the red ball, and the solution can be solved: (1) The frequency of participating in this game to get Hypertherm toys m n = 8000 40000, that is, m n = 1 5

2) If there are m balls in the bag, the probability of touching the red ball p (red ball) = 8 m, 8 m 1 5

The solution is m 40, so the white balls are close to 40-8=32.

（1）8000÷40000=

The frequency of participating in this event to get Hypertherm toys is:

2) There are x white balls.

8÷（8+x）=

x = 32 white balls in 32 bags.

If there is no condition, due to the sine x r

This question x r

1) If you have learned factorial, then it is 3! =6

2) Since the ticket needs to indicate the name of the station, the name of the departure station is different, and there are two possibilities for the station corresponding to each fare.

3！x 2 = 12 species.