What is the answer to square of X + X-1 + 2 = x + 2x of 1?

What is the answer to square of X + X-1 + 2 = x + 2x of 1?

(x-1)/(x²+x)+2=2x/(x+1)
The equation is multiplied by X & sup2; + X at the same time
X-1 + 2x & sup2; + 2x = 2x & sup2;, where x ≠ 0 and X ≠ - 1
The above formula is reduced to 3x-1 = 0
The solution is x = 1 / 3

(x + 3) 2 square = 2x + 6 solution

Square of (x + 3) = 2x + 6
The square of (x + 3) = 2 (x + 3) (x + 3) - 2 (x + 3) = 0 (x + 3-2) (x + 3) = 0 (x + 1) (x + 3) = 0x1 = - 1 x2 = - 3
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The equation kx2 - (k-1) x + 1 = 0 of X has rational roots, so we can find the value of integer K

(1) When k = 0, x = - 1, the equation has rational roots. (2) when k ≠ 0, because the equation has rational roots, if K is an integer, then △ = (k-1) 2-4k = k2-6k + 1 must be a complete square, that is, there is a non negative integer m, such that k2-6k + 1 = m2

The total resistance of the transmission line between a and B is 10 Ω. The power transmitted from a to B is 11000 kW, and the transmission voltage is 220kV? (2) How much power is lost on the transmission line? (3) From the point of view of energy conversion, what is the essence of energy loss on transmission line? (answer in words)

(1) From P = UI, I = Pu = 11000kW, 220kV = 50A; answer: the transmission current is 50A. (2) P = I2R = (50a) 2 × 10 Ω = 25000w; answer: the electric power lost on the transmission line is 25000w. (3) if the transmission line has resistance, the current will generate heat when passing through the transmission line, which will convert the electric energy into internal energy

It is known that f (x) = x & # 178; - 1, f (x + X & # 178;)
Given f (x) = x & # 178; - 1, find f (x + X & # 178;)

f(x+x²)=(x+x²)²-1
=x²+2x³+x^4-1
So f (x + X & # 178;) = x ^ 4 + 2x & # 179; + X & # 178; - 1

A refrigerator, power consumption is 0.72kw.h/24h, rated voltage is 220V, input power is 120W
It took 6 minutes for the refrigerator to start and stop working, and the electric energy meter turned 18 circles. When the refrigerator was working according to the rated power consumption, the actual working time of the day was? H, started? Times, and the electric energy meter turned? Circles for each degree of electricity consumed. The last empty was 6000. How about the first two empty!
Finally, a blank. Am I right?

720/120=6h,
60 * 6 / 6 = 60 times
18 * 60 / 0.72 = 1080 cycles / 0.72 = 1500 cycles / kW. H
The actual working time of refrigerator is 6 hours, starting 60 times, and the dial of electric energy meter turns 1500 times per kilowatt hour consumed

What's 99 times 21 / 50

99x21/50
=(100-1)x21/50
=100x21/50-21/50
=42-21/50
=41 and 29 / 50

The circuit of using LED as indicator light of 220 V power supply (the simplest)
Can we just string one resistor? Look at someone who only string one resistor,

The book says that a reverse diode should be connected in parallel on the LED, but I don't think many electrical appliances are connected in parallel. It can also be used when directly connected to the mains power, and it won't reverse breakdown!
I think it's decided by the characteristics of the LED. Although it has been reverse breakdown at that time, it will not be damaged due to the protection of series resistance, so it can be used either way!
Breakdown diode is not necessarily damaged, but also can recover. Just as the regulator is used in reverse breakdown

40 -------- =0.625=（ ）÷16=（ ）% （ ）

40/64 =0.625=（10 ）÷16=（62.5 ）% =25/40

If two resistors R1 = 6 ohm and R2 = 18 ohm are connected in series, then I1: I2 = () U1: U2 = ()

If two resistors with R1 = 6 ohm and R2 = 18 ohm are connected in series, then I1: I2 = (1:1) U1: U2 = (1:3)
Analysis: because R1 and R2 are in series, I1 = I2, so I1: I2 = 1:1
∵ I1: I2 = 1:1, R1: R2 = 6 Ω: 18 Ω = 1:3
∴U1:U2=1:3
I hope my answer will help you