General score: x + 2 / 2x + 2, X / X & sup2; - x-2,3 / 8-4x

General score: x + 2 / 2x + 2, X / X & sup2; - x-2,3 / 8-4x

（x+1）²/x
-（x²+2x-1）/x
（3-32x）/8

Simplification (2x + 1) (x-1) (x + 2) and factorization (2x-5) (x-3) + (3x-1) (5-2x)

(2x+1)(x-1)(x+2)=(2x^2-x-1)(x+2)=2x^3+4x^2-x^2-2x-x-2=2x^3+3x^2-3x_ 2 (2x-5) (x-3) + (3x-1) (5-2x) = (2x-5) (x-3) - (3x-1) (2x-5) (with common factor extraction) = (2x-5) (x-3-3x + 1) = (2x-5) (- 2x-2) (the first item in brackets

Using factorization to simplify: 1 + X + X (1 + x) + X (1 + x) ^ 2 + +x(1+x)^2004.

1+x+x(1+x)+x(1+x)^2+…… +x(1+x)^2004.
=(1+x)+x(1+x)+x(1+x)^2+…… +x(1+x)^2004.
=(1+x)(1+x)+x(1+x)^2+…… +x(1+x)^2004.
=(1+x)²+x(1+x)^2+…… +x(1+x)^2004.
=(1+x)²(1+x)+…… +x(1+x)^2004.
=(1+x)³+…… +x(1+x)^2004.
=(1+x)^2005

Simple calculation (1 / 1994) ^ 1999 * (- 1994) ^ 2000

（1/1994）^1999*（-1994）^2000
=(1994)^(-1999)*(1994)^2000
=1994^(-1999+2000)
=1994

We know that A1 = 1 / 2 point (n, 2An + 1-an) in sequence an is on the straight line y = x, where n = 1,2,3 An + 1 in (n, 2An + 1-an) is a diagonal sign
(1) Let BN = an + 1-an-1 prove that the sequence BN is an equal ratio sequence (an + 1 in BN = an + 1-an-1 is a corner mark)
(2) Finding the general term of sequence an

(n, 2A (n + 1) - an) on the line y = x, then n = 2A (n + 1) - an,
Then n + 1 = 2A (n + 2) - A (n + 1), subtracting the two formulas, then 1 = 2A (n + 2) - 3A (n + 1) + an,
Let's get 2B (n + 1) = BN, which proves that if BN is solved, then TN will be solved
Divide both sides of n = 2A (n + 1) - an by the nth power of 2 at the same time, sum them up to get an, then find Sn, and use the formula of the middle term,

50%X+3/7X+450=1/4X

Move to general score: 1 / 2x + 3 / 7x-1 / 4x = - 450 14 / 28x + 12 / 28x-7 / 28x = - 450 19 / 28x = - 450
x=-450*28/19 x=1260/19

A barrel of oil weighs 32 kg. After 60% of the oil is poured out, the barrel still weighs 14 kg. How many kg does the original barrel weigh?

idfsddfs ,
(32-14) △ 60% = 30 (kg)

Piecewise function is a constant at x = 0. How to find the derivative at 0? We can't default that the derivative is continuous

First, we have continuity at x = 0
Secondly, calculate the derivatives at x = 0 - and x = 0 + to see if they are equal

To solve the equation x + 1 / 7 x = 56 x-4 x = 36

X + 1 / 7 x = 56
Multiply both sides by 7 to get
7x+x=56×7
8x=56×7
x=7×7
x=49
X-4 of x = 36
3 / 4 x = 36
Quarter x = 12
x=48

A cylindrical water pipe, with an inner diameter of 20 cm, has a flow rate of 3 meters per second. How many cubic meters of water can this water pipe flow in one minute?

The radius is
20 △ 2 = 10 (CM) = 0.1 (m)
1 minute running water
0.1 × 0.1 × 3.14 × 3 × 60 = 5.625 (M3)