Junior 3 math winter vacation homework questions, junior 3 math winter vacation homework

The answer is that B first solves the root number.

b a+a b-2=(b 2+a 2-2ab) ab because a so (b a+a b-2)= b-a) 2 ab]=[b-a) (ab)] ab).

This question involves the application of the completely flat method and the rationalization of the denominator, and it is a scoring question for the high school entrance examination. . . I have taken a few sessions of high school entrance examination mathematics, and your efforts have been great.

Select B to parse.

b a+a b-2=b ab + a ab-2ab ab=(b-a) ab

Then the above formula is squared to obtain [(b-a) (ab)] ab) need to pay attention to a few points: a b so (a-b) square = b-a denominator should be physical.

Choose a and give the root number to the pass.

Proof: (1) (2x)2+4x+3 (2) (3x)2-5x-1 - 2x)2-4x-7

4x2+4x+3 =9x2-5x-1-4x2+4x+7

4(x2+x+3/4) =5x2-x+6

4(x2+x+1/4-1/4+3/4) =5(x2-1/5x+6/5)

4〔(x+1/2)2+1/2〕 =5(x2-1/5x+1/100-1/100+6/5)

4(x+1/2)2+2 =5〔(x-1/10)2+119/100〕

x+1/2)2≥0 =5(x-1/10)2+119/20

4(x+1/2)2≥0 ∵(x-1/10)2≥0

4(x+1/2)2+2>0 ∴5(x-1/10)2≥0

For any real number x, there is always 5(x-1 10)2+119 20>0

2x)2+4x+3>0 For any real number x, the value of 3x)2-5x-1 is always greater than the value of (2x)2-4x-7.

(1) (2x)²+4x+3＝4x²+4x+3＝4（x²＋x）＋3＝4（x＋¼）1＋3＝4（x＋¼）2

Since (x)0 then 4(x)2 0(2) is the original formula: prove that (3x) 5x 1 (2x) 4x 7 is an arbitrary real number for x.

First, shift the two sides to the simplest form as follows: 5x x 6 0; That is, it is proved that 5x x 6 0 is an arbitrary real number for x. Then there are:

5（x－1／10）²＋6－1／20＞0

Because 5 (x 1 10) 6 1 20 0 is constant, then (3x) 5x 1 (2x) 4x 7 is an arbitrary real number for x.

Be sure to give me a point.

o( o haha

m = 0, x is about equal to 2, and after putting into production, the enterprise will be able to recoup its investment in the second year.

If you're sure that there's nothing missing and that the full title is like that, then I can tell you with certainty"The question is wrong, and a condition is missing"

This question has an Olympiad problem, which is very similar to it, and the original question is like this.

When a group of people set off for a grand annual picnic, each car loaded exactly the same number of people. There were 10 cars broken down on the way, so the rest of the cars had to be loaded with one more person each. When they set off for home, they found that 15 more cars were out of service, so on the way home, there were three more people in each car than when they left in the morning.

Excuse me: How many people attended this grand annual picnic?

How many cars, how many people are in each car?

You look carefully at your topic"There were 10 cars broken down halfway through, so there were 3 more people left than when they left in the morning"There is an obvious semantic error between these two sentences, the first half of the sentence is still about the departure, and the second half of the sentence is about the way back.

So, obviously, the topic is wrong.

Manual labor, satisfied, thank you--

So pf 2 = pa*pd

Because PE=PF

So PE2=PA*PD

Thus it is easy to prove the pae pde

So pea= pde, and pde= cba, so pea= cba

So pe bc

I don't understand whether E is a tangent or F is a tangent point?