Math problems difficult, many, but rewarding .

1. Discuss with classification.

1) When x-3>0.

Original = x 2 -6x + ax - 2x -3a + 6 + 9-2a = 0 x 2 - (8-a) x + 15-5a = 0

Because there are two unequal real roots.

So >0

i.e. (8-a) 2 -60+20a>0

64-16a+a^2 -60+20a>0

a^2 +4a+4>0

a+2)^2>0

So a≠-2

2) When x-3=0.

Original = x 2 -6x + 9-2a = 0

Same with >0

So 36+36-8a>0

a<93) when x-3<0.

Original = x 2 -6x-ax + 2x + 3a - 6 + 9 - 2a = 0 x 2 - (4 + a) x + a + 3 = 0

Same with >0

So 16+8a+a 2 -4a-12>0

a^2+4a+4>0

So a≠-2

In summary, a<9 and a≠-2

Not the same answer as yours? That's the answer you wrote, right?

You don't write very clearly, in the details point.

Substituting x=12,y=0 to get 144a+12b+c=0 and substituting x=0,y==getting c=

Substituting c= and simplifying it to 60a+5b+1=0......If a>0

b/2a>=12

b = <-24a substituted to -60a + 1> = 0

So 0-1 5

When -1 50

then -b 2a>0

So a<0

In summary, the value range of a is a=<1 60 and a= 0

The volume of the iron cone is 3*3*cubic centimeter.

And the bottom area of the container: 4*4*cm².

The height of the increase in the row of water sunflowers: cm.

So the water depth of Minghuai is 15+ cm.

The volume of the iron cone: 1 3

Standing bucket royal filial piety square centimeter.

Cylindrical base area:

Cm. Increase the water level at this time:

Demolition of noisy centimeters. At this time, the water depth:

Centimeter blank draft.

Because A and B take equal time, the distance ratio is the speed ratio.

The east and west towns are located x meters apart. According to the title:

2/5)x／960=x/(1-3/11)x960=2/5x×8/11

x=960×11/8×5/2=3300

Let's start with the second condition.

When A arrives in Xizhen, B still has 3 11 for the whole journey, that is, B has gone through the whole 8 11, so the speed ratio of the two is.

Looking at the first condition again, we now know that the speed ratio of the two is.

11 8, so A went the whole way.

, B walked the whole way.

2 5) * (8 11) = 16 55, B is gone.

meters, so the whole length is. Rice.

t stands for "Industrial Science", and there are 2 such books! (-5-2-010 2, 5 for shelf 5, 2 for the second floor, 010 for the number of books, 2 for the number of such books.)

Reference: A Brief Table of Chinese Book Classification.

It should be 27m = () km.

1km=1000m

In turn 1m =

So 27m = km

27m=

The conversion between them is 1000

I don't see what you mean, 27m?

1, because the function f(x) = (ax+b) (1+x 2) is an odd function on (-1,1), and f(1 2) = 2 5

So f(-x) = -f(x).

Then f(-1 2)=-2 5

The substitution function f(x) has.

The equation is a+2b=1;

a-2b=1.

The solution yields a=1 and b=0

So f(x)=x 1+x 2

Establish. 10,1+x1 2)(1+x2 2)>0 so f(x1)-f(x2) i.e. f(x1) so f(x) on (-1,1) is the posture and god mask increase function.

2. Let t-1=x

So t=x+1

f(t) is defined in the domain of .

The range of 0f(t-1) is -1 21 2(x+1) 1+(x+1) 2<0

Let's do it yourself.