Absolutely strong! Come on, math

Wait, what grade or junior high school are you doing on this topic? High school? I'm a math top student in my class, but let's talk about it first! I'll think about whether I want to help you!!

1.Xiao Ming is doing a math problem: "Two polynomials a and b, where b = 3a 2-5a-7, when trying to find a+2b", he mistakenly regarded a+2b as a-2b, and the answer he found was:

2a 2+3a+6, can you help him calculate the correct answer for a+2b? (Write out the calculation process).

a-2b=-2a^2+3a+6=a-2(3a^2-5a-7)=a-6a^2+10a+14

a=4a^2-7a-8

a+2b=4a^2-7a-8+2(3a^2-5a-7)=10a^2-17a-22

Please calculate according to the calculation method of the above formula.

3+1)(3^2+1)(3^4+1)……3 32 + 1) - 3 out of 2 64

Let a=(3+1)(3 2+1)(3 4+1)......3^32+1)

Then 2a = 2 (3 + 1) (3 2 + 1) (3 4 + 1) ......3^32+1)

then a=(3 64-1) 2

3+1)(3^2+1)(3^4+1)……3 32 + 1) - 3 out of 2 64

a-3^64/2

Move the decimal point to the right by two places to get a new number, the original number is different, the original number is the prop used by Class 51 to make the performance program of Children's Day 1 To make an 18m long red cloth into a right-angled triangle with a right-angled side, how many such pennants can be made? (columnar calculation).

There is a trapezoidal vegetable field, the upper bottom is 15m long, the lower ground is 28m high, if the income per square meter of vegetables is 2 yuan, how much is the total income of this vegetable field?

Yuanyuan turns the pointer and clearly guesses which number the pointer will listen to If you guess correctly, you win if you guess wrong, you win Yuanyuan. (Title below).

Is this game fair for both parties? Why? Is it a sure number?

Now there are four ways to guess the number, if you were Mingming, which one would you choose? Please explain why.

It's not an integer multiple of two, it's not an integer multiple of three.

Numbers greater than 7 Numbers less than 7.

**: Unfair, it may be 1 6

Not an integer multiple of 3, there are 4 possibilities, the probability is 4 6 = 2 3

The game is not fair, and it is more likely that you will guess wrong, but you will not necessarily lose.

"Not an integer multiple of 3" will be chosen, which will have the best chance of winning, which is 2 3

The triangular ADE is similar to the triangular CDF.

So ad:cd=5:8 ad=10 cd=16bf=8 root number 3

ae = 5 root number 3

BE+BF=6+3, root number 3

Solution: Solution: It takes Xiao Ming x minutes to walk to school every day, and it takes 1 3x to run.

Half of the run is 1 2 x 1 3x minutes, half of the walk is 1 2x minutes, and half of the run takes 10 minutes less than half of the walk; According to the title:

1/2x-1/2*1/3x=10

1/2(x-1/3x)=10

x=30 It takes 30 minutes for Tom to walk to school every day.

I'm a teacher, thank you.

Let the walking speed be x, and the daily walking time to school is y, then, 3x*(y 10) xy

3y-30=y

y=15 so the school time is 15 minutes.

It takes 30 minutes to walk to school every day.

Let the distance to school be s, the speed of the small walk v, then the speed of running is 3v solution s v=30 (minutes).

Let Xiao Ming's walking speed be xm s, then the running speed will be 3xm s by the title: s x=s 2x+s 6x+600 so s 3x=600

So t=s x=1800 seconds.

So it takes 1,800 seconds, or 30 minutes, to walk.