1/(2-x)²,x/x²-4 Using common points, we need to do it now,

1/(2-x)²,x/x²-4 Using common points, we need to do it now,

solution
The simplest common denominator is: (X-2) &# 178; (x + 2)
∴
1/(2-x)²=1/(x-2)²=(x+2)/(x-2)²(x+2)
x/(x²-4)=x/(x-2)(x+2)=x(x-2)/(x-2)²(x+2)

3²-2²）²+（4²-3²）²+（5²-………… ＝?
3²-2²）²+（4²-3²）²+（5²-4²）²+6²-5²）²=?

Original formula = 25 + 49 + 9 + 121 = 204

Half X & # 178; + seven half x + 5 = 0
Such as the title

1/2*X*X+7/2*X+5=0
Multiply both sides of the equation by 2 to get:
X * x + 7x + 10 = 0, then factoring
(x + 2) * (x + 5) = 0, so:
X = - 2 or - 5

A pile of nine tenths of a ton of coal, two fifths of it, less than a ton of coal?

9 out of 25 tons

How to judge the definite of one positive two definite three phase equal mean inequality
such as
X2 + 2x + 3 + 1 / (x2 + 2x + 3) can't use mean inequality directly, but x2 + 1 + 1 (x2 + 1) can be used directly. What's the matter?

"Fixed" is "fixed value", that is, the product of two numbers must be constant
X2 + 2x + 3 + 1 / (x2 + 2x + 3) can not be directly used as mean inequality, but x2 + 1 + 1 / (x2 + 1) can be directly used. This is not a definite problem, but an "equal" problem. The former has no solution when x2 + 2x + 3 = 1 / (x2 + 2x + 3), while the latter has solution x = 0 when x2 + 1 = 1 / (x2 + 1)

The length of the railway is 490 km, with 72 km per hour for Party A and 68 km per hour for Party B. when the two trains met, they went in different directions
How many kilometers did you travel?

Encounter time: 490 △ 72 + 68 = 490 △ 140 = 3.5 hours
Then a driving: 72 × 3.5 = 252km
B: 68 × 3.5 = 238km

Finding the system of inequalities x-3 (X-2) > 1 2x-1 / 5 ≥ x + 1 / 2

x-3(x-2)>1
x-3x+6>1
-2x>-5
x

The distance between a and B is 560 km. A passenger train and a freight train leave from a and B at the same time. After 3.5 hours, the two trains meet. The passenger train travels 95 km per hour. How many km per hour is the shape of the freight train

Suppose that the shape of freight car per hour is x km, and the equation is formulated according to the meaning of the problem
3.5(x+95)=560
3.5x+315=560
3.5x=245
x=70
A: the truck is 70 kilometers per hour
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The equation of a circle passing through three points a (1,12) B (7,10) C (- 9,2)

Let the circular equation be (x-a) &\35\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\theequation of circle is (x-1) &# 178; + (Y-2) &#

The two engineering teams of Party A and Party B build a road, and assign the task according to the number of the two teams. When the task is completed, team a will build 2.4km less than team B. It is known that the number ratio of the two teams is 7:8. How many kilometers is the road?

According to the title, the ratio of the length of the road is 7:8
Therefore, the total length of the road is 2.4 / (8-7) * (8 + 7) = 36km