Good math is coming, good math is coming

Because so. Scientific truth.

1 and 2 are just a recognized name, they each represent a certain quantity, if you change the name for them, but the amount represented remains the same.

Because if you add one object to one object, you get two.

I remember someone proved that 1+1=2, but who I don't remember, why do you ask this? Almost no one will....

Quality after one year.

m=m0-m0*10%=m0 (1-10%) mass after 2 years.

m=m0(1-10%)-m0(1-10%)*10%=m0(1-10%)²

T years post-quality.

m=m0(1-10%)^t

m=9/10*m0%^t

t-power) half-life calculation.

m/m0=(m0(1-10%)^t/m0=1-10%)^t=

9/10)^t=1/2

Take 10 at both ends as the base logarithm to get it:

t*lg(9/10)=lg(1/2)

t*(lg9-lg10)=lg1-lg2

t(2lg3-lg10)=-lg2

t=-lg2 (2lg3-lg10)=year.

I don't know how much power is consumed by induction cookers, computers, washing machines, and water dispensers, how to calculate them???

You're really bad at math, and the people who can do it haven't been born yet.

1 Set the price to be $x according to the title.

Solve x=20 (yuan).

2 Set the athlete to have x people, and the funding is y yuan according to the title.

y-7x=140

10x-y=100

Solve this system of equations to get it.

x=80 (person).

y=700 (yuan).

.5a+

2. Obtained from the question: a=71 13, b=17 1314a-2b=960 13

3. For example: 123 can have: 12, 21, 13, 31, 23, 32, and the three-digit number is a*100+b*10+c(abc) Yes: ab,ba,,bc,cb

ab+ac+bc+ba+cb+ca=(a*10+b)+(a*10+c)+(b*10+c)+(b*10+a)+(c*10+b)

c*10+a)=20*(a+b+c)+2*(a+b+c)ab+ac+bc+ba+cb+ca)/(a+b+c)=20+2=22

The absolute value of m+4 + (n-3) to the power of 2 = 0, then mn + m to the power of 2 = (64).

2. When n is a positive integer, (-1)2n to the power = (1), 1) 2n+1 to the power = (-1).

3. If m is greater than 0 15 n is less than 0, then mn( <0 ;

Students, you have to study hard, in fact, the questions are not difficult, even if you have just learned these, it should be the foundation.

(1) Obtained from the question|2m+4|=0 (n-3) 2=0, so m=-2 n=3 then (mn+m) 2=64 (2) even, odd (3) mn 0

1. Because the absolute value of 2m+4 and the power of (n-3) are both positive, it is impossible to have a positive and negative situation, and only the case is 0, so we get m=-2, n=3, and the rest is calculated by ourselves.

n is an even number, 2n+1 is an odd number, think for yourself.

N less than 0 means that n is negative, and m is greater than 0, so mn is less than 0 and agrees with the first floor.

Each feeding is 24 hours, i.e. 1 day.

So the 10th feed, remove the first one, and there are 9 more.

Therefore, 4 days and 12 hours should be added.

That is, 8 o'clock in the morning on July 10.

Feed every 12 hours, and the 10th feed at 8 a.m. on July 10

Analysis: The first feed is 8 p.m. on July 5, the second time is 8 a.m. on July 6, the third time is 8 p.m. on July 6, the fourth time is 8 p.m. on July 7, the fifth time is 8 p.m. on July 7, the sixth time is 8 p.m. on July 8, the seventh time is 8 p.m. on July 8, the eighth time is 8 a.m. on July 9, the ninth time is 8 p.m. on July 9, and the tenth time is 8 a.m. on July 10.

If this time is counted as 0 times at 8 o'clock on July 5, 10 12 hours is 5 24 hours = 5 days, the 10th time is 8 o'clock in the evening on the 10th, if this time is counted as the first time at 8 o'clock on July 5, then it is 9 12 hours, which is 4 and a half days, and the 10th time is 8 o'clock in the morning on the 10th.