Who knows 7th grade math and who can math 7th grade questions?????

The heat released by the complete metamorphosis of these radiums is equivalent to the heat of burning a ton of coal.

3a^2b+5c)(3a^2b-x)=9a^4b^2+3a^2b(5c-x)-5cx=9a^4b^2-y

So there is 3a 2b(5c-x)=0,5cx=y.Solve x=5c, y=25c2

Then it is 9a 4b 2-25c 2=(3a 2b+5c)(3a 2b-5c).

m/2+x)^2=m^2/4+xm+x^2=m^2/4+mn/3+y

So there is xm=mn 3 and x 2=ySolve x=n 3, y=n 2 9

Then there is m 2 4 + mn 3 + n 2 9 = (m 2 + n 3) 2

x^2-6ax+9a^2=(x^2-3ax)-(3ax-9a^2)=x(x-3a)-3a(x-3a)

x-3a)(x-3a)=(x-3a)^2

x-2a)^2-a(2a-x)=(x-2a)(x-2a)+a(x-2a)=(x-2a)(x-2a+a)=(x-2a)(x-a)

Let 4x 2+bx+36=(mx+n) 2=m 2x 2+2mn+n 2, then there is 4=m 2, b = 2mn, 36=n 2

The solution gives m = 2 and n = 6, then mn = 12, i.e. b = 2mn = 24

3a^2b+5c)(3a^2b-x)=9a^4b^2+3a^2b(5c-x)-5cx=9a^4b^2-y

So there is 3a 2b(5c-x)=0,5cx=y.Solve x=5c, y=25c2

Then it is 9a 4b 2-25c 2=(3a 2b+5c)(3a 2b-5c).

m/2+x)^2=m^2/4+xm+x^2=m^2/4+mn/3+y

So there is xm=mn 3 and x 2=ySolve x=n 3, y=n 2 9

Then there is m 2 4 + mn 3 + n 2 9 = (m 2 + n 3) 2

x^2-6ax+9a^2=(x^2-3ax)-(3ax-9a^2)=x(x-3a)-3a(x-3a)

x-3a)(x-3a)=(x-3a)^2

x-2a)^2-a(2a-x)=(x-2a)(x-2a)+a(x-2a)=(x-2a)(x-2a+a)=(x-2a)(x-a)

Let 4x 2+bx+36=(mx+n) 2=m 2x 2+2mn+n 2, then there is 4=m 2, b = 2mn, 36=n 2

The solution gives m = 2 and n = 6, then mn = 12, i.e. b = 2mn = 24

1) I didn't understand the first question in the first question, and the coefficient is -1

2) 2 3ab -5 7

3)m/（n-t) -m/n

4)2010*(1-1/2)*(1-1/3)*(1-1/4)*.1-1 2010).

I don't have the textbook you said at hand-, I hope Jian Hui can help you.

Defeat front: (1) The number of times z is 0, and the coefficient is -12) 2 3ab -5 7

3）m/（n-t) -m/n

2010*(1/2*2/3*3/4*..2009 2010) (of which the middle item is about to be divided, and 1 2010 remains).

So the equation = 2010 * 1 2010 = 1

1) The number of times z is 0, and the number of pickpockets is -1.

2) is a 2-time binomial, a binomial is 3ab-5 7, and a constant term is 3ab-5 7

3）m/(n-t)-m/n

Set A cup of coke and B cup of milk tea.

So 2a+3b=20

a=（20-3b）/2

If a is an integer, it must be (20-3b) 2 an integer.

That is, 20-3b is an even number.

And 20 is an even number.

So 3b must be an even number.

Consider setting b=2k

So a=10-3k

and a 0 b 0

So 1 k 3

So there are three ways.

7 cola 2 milk tea.

4 cola 4 milk tea.

1 cola 6 milk tea.

The second question is the way

I didn't understand it at all, and the original question was easy to post?

Problem solving idea: It is known that 'A and B have a total score of 740 points', so you need to consider using a binary equation, you can first set up class A with x people, and class B with y people, and then according to 'class A gets an average of 70 points per person, and B gets an average of 60 points per person', you can list the formula 70x+60y=740. From 'A and B students in class A', x+y=a

Problem solving process: Solution: There are x people in class A and y people in class B.

From the title, 70x+60y=740

x+y=a is a two-way solution.

x=2，y=10.or x=8,,y=3

This kind of problem is solved with this idea, but the total number of A and B given in this question is A, not a specific number, so you should consider using an integer to try to replace people, because people are whole numbers.

Suppose there are x people in class A and y people in class B, 70*x+60*y=740, and then try to get the number x=1,y=no, x=2,y=10 is okay, x=3,y=no, x=4,y=no, x=5,y=no, x=6,y=no, x=7,y=no, x=8,y=3 is okay, x=9,y=no, x=10,y=no, Therefore, there are 2 people in class A and 10 people in class B, or 8 people in class A and 3 people in class B.

Problem solving process: Solution: There are x people in class A and y people in class B.

From the title, 70x+60y=740

x+y=a is a two-way solution.

x=2，y=10.or x=8,,y=3

There are x people in class A and y people in class B. From the meaning of the title:

70x+60y=740.

x+y=a。

Since x and y are both integers, and a is also an unknown integer, it is good to use integers as an integer.

Solution: x=2, y=10. or x=8,,y=3

There are x people in class A and y people in class B.

Then there is x+y=a 70*x+60*y=740

Substituting x=a-y into 70*x+60*y=740, you can solve y, and then substitute y into x+y=a, and you can solve x.

I will too, if you don't know what to type, everyone can help you find a way.

The degree of this angle is 45 degrees.

n=0n-2=-2<0，n+3=3>0

The point (n-2, n+3) must be in the second quadrant.

x,x+1,x+7,x+8

No, because x is a decimal at this point, which does not fit the topic.