2 / x-1,1-3x / 2-2x, 2 / x-1,1-3x / 2-2x,

2 / x-1,1-3x / 2-2x, 2 / x-1,1-3x / 2-2x,

I can't see clearly, can I
(2/x) - 1=2/x +(x/x=(2+x)/x
(1-3x)/2 - 2x=(1-3x)/2 -4x/2=(1-7x)/2
Please clarify the title

General score: (1) 2 / x ^ 2 + x-2,1 / x ^ 2-2x-8 (2) x / x ^ 2-3x-4,1 / x ^ 2-8x + 16

(1) By 2 / (X & # 178; + X-2) = 2 / (x + 2) (x-1), by 1 / (X & # 178; - 2x-8) = 1 / (x + 2) (x-4), their common denominator is (x + 2) (x-1) (x-4) ‖ 2 / (X & # 178; + X-2) = 2 (x-4) / (x + 2) (x-1) (x + 4) 1 / (X & # 178; - 2x-8) = (x + 2) / (x + 2) (x-1) (x + 4) (2)

X ^ - 1 / 1, x ^ - 3x + 2 / 1

1/（x^2-1=1/〔（x+1）（x-1）〕=（x-2）/〔（x+1）（x-1）（x-2）〕
1/x^2-3x+2=1/〔（x-2）（x-1）〕=（x+1）/〔（x+1）（x-1）（x-2）〕

General score: 1 / X-1, 2 / 3x

: 1 / X-1
=3x/3x(x-1)
2/3x
=2(x-1)/3x(x-1)

It is known that the parabola C: x ^ 2 = - 2 (y-m), points a, B and P (2,4) are all on the parabola, and the inclination angles of PA and Pb are complementary
(1) Verification: the slope of line AB is a fixed value
(2) When the intercept of the line AB on the y-axis is positive, the maximum value of s △ ABP is obtained

【1】 It is proved that: (1) on the parabola y = (- 1 / 2) x & sup2; + H, point P (2,4) is 4 = (- 1 / 2) × 2 & sup2; + H
∴h=6.
The parabola y = (- 1 / 2) x & sup2; + 6
② ∵ points a and B are on the parabola, so we can set their coordinates as a (2a, 6-2a & sup2;), B (2B, 6-2b & sup2;) (a ≠ b)
③ According to the problem, if the inclination angle of the straight line PA is β, then the inclination angle of the straight line Pb is π - β
The slope formula shows that kPa = Tan β. KPB = Tan (π - β) = - Tan β
That is to say, the sum of the slopes of the two lines PA and Pb is 0
From the slope formula, it can be obtained that kPa = (2-2a & sup2;) / (2a-2) = - (a + 1)
Kpb=(2-2b ²)/(2b-2)= －(b+1).
∴[-(a+1)]+[-(b+1)]=0.∴a+b=-2.
④ According to the slope formula, KAB = [(6-2a & sup2;) - (6-2b & sup2;)] / (2a-2b) = (B & sup2; - A & sup2;) / (a-b) = - (a + b) = 2
The slope of line AB is constant 2
① The slope of the straight line AB is 2, so we can set its "oblique equation" as y = 2x + t
Moreover, the longitudinal intercept of line AB is positive, t > 0
The simultaneous parabolic equation y = (- 1 / 2) x & sup2; + 6 and the linear equation y = 2x + t
x ²+4x+2(t-6)=0.
The discriminant ⊿ = 16-8 (T-6) = 8 (8-t) > 0. 0 < T < 8
② According to the "chord length formula of conic curve", chord | ab | = √ [40 (8-t)]
According to the formula of distance from point to line, the distance d from point P (2,4) to line AB: y = 2x + T is:
d=t/(√5).
The area of triangle ⊿ PAB s = (1 / 2) ×| ab | × d = (1 / 2) × √ [40 (8-t)] × T / (√ 5)
=√[2t²(8-t)]= √[2(-t³+8t²)].
③ Now let's find the maximum value of the function f (T) = - T & sup3; + 8t & sup2;, (0 < T < 8)
The derivation gives f ′ (T) = - 3T & sup2; + 16t. = - t (3T-16)
It is easy to know that in the interval (0,8), when 0 < T < 16 / 3, f ′ (T) > 0
When 16 / 3 < T < 8, f '(T) < 0
It can be seen from "the relationship between the monotonicity of function and the positive and negative of its derivative",
When t = 16 / 3, the area of ⊿ PAB is the largest
④ When t = 16 / 3, s = (64 √ 3) / 9 can be obtained from S = √ [2T & sup2; (8-t)]
The maximum value of ⊿ PAB area is (64 √ 3) / 9
I hope I can understand~

7 out of 15 (2 / 3 minus 3 / 13) =?

7 / 15 (2 / 3 - 3 / 13)
= 7/15 - 2/3 + 3/13
= 3/13 - 3/15
= 2x3 / ( 13x 15)
= 2/ 65
I wish you every day!

Where H + k is a constant, then H + k =?

x²-2x-3
=(x²-2x+1)-3-1
=(x-1) & sup2; - 4, where h = 1, k = - 4
h+k=1+(-4)=-3

7x9 + 12 / 3 - 2 = 35, add brackets to make the formula true

7*[(9+12)/3-2]=35

X & # 178; + Y & # 178; + 4x-6y + 15 to find the minimum value of XY formula
X & # 178; + Y & # 178; + 4x-6y + 15 to find the minimum value of X Y formula
There is also an example of making the formula equal to zero!

The original formula = x \\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\and

A and B are both natural numbers, and B multiplied by 10 / A is less than B, B multiplied by 8 / A is greater than B, find the value of A. please write the answer and the reason

The answer is a = 9
The reason is as follows: B multiplied by 10% a is less than B, which means that a / 10 is less than 1, that is, a is less than 10
B multiplied by 8 of a is greater than B, indicating that a / 8 is greater than 1, that is, a is greater than 8
And a and B are both natural numbers
So a can only be 9