Given X & # 178; + X-1 = 0, find the value of (x + 1) (X & # 178; - 2x + 6) - (- x) &# 178; + (2x-1) &# 178;)

Given X & # 178; + X-1 = 0, find the value of (x + 1) (X & # 178; - 2x + 6) - (- x) &# 178; + (2x-1) &# 178;)

Given X & # 178; + X-1 = 0, then: X & # 178; = - x + 1
So:
(x+1)(x²—2x+6)-(-x)²+(2x-1)²
=(x+1)(-x+1-2x+6)-x²+4x²-4x+1
=(x+1)(-3x+7) +3x²-4x+1
=-3x²+4x+7+3x²-4x+1
=8

Do 105 watt CFLs use the same amount of electricity as 105 watt incandescent lamps?

105 watts is its power consumption, so their power consumption is basically the same. Due to the power factor, their power consumption composition is different

1. It is known that in △ ABC, a (2, - 1), B (3,2), C (- 3, - 1), ad is the height on the edge of BC, and find (1) │ Ad vector │; (2) the coordinates of point D
2. In the rectangular coordinate system, given the vector OA = (4, - 4), the vector ob = (5,1), the projective quantity of the vector ob in the direction of the vector OA is │ om vector │, the coordinates of the vector MB are obtained
3. In the quadrilateral ABCD, the vector AB = a, BC = B, CD = C, Da = D, and a * b = b * C = C * d = D * a, judge the shape of the quadrilateral
4. Three points a (2,1), B (3,2), D (- 1,4) are known. To make the quadrilateral ABCD a rectangle, find the coordinates of point C, and find the cosine of the acute angle between the two diagonals of rectangle ABCD
--------------------------------------------------------------------------------------------------------

(1) Let D point coordinate be (x, y), then ad = (X-2, y + 1), BC = (- 6, - 3), BD = (x-3, Y-2) because ad is the height of BC, so ad · BC = 0, that is - 6 (X-2) - 3 (y + 1) = 0 (a) And because D is a point on BC, there is BD / / BC, that is, (x-3) / (- 6) = (Y-2) / (- 3) (b) The solutions of simultaneous equations (a), (b) are as follows

A and B bulbs are marked with 220v40w and 220v60w respectively, and they are connected in series in the circuit of 220 v. which actual power is higher has specific analysis

The resistance of 220v40w and 220v60w are 1210 ohm and 807 ohm respectively
Series current equal power P = I ^ 2R
So the power of resistance is higher than that of 40W

Simplified calculation of 20 / 8 / 21 * 14 / 15

20 of 21 / 7 of 8 * 14 of 15
=20/21 *8/7 *14/15
=64/63

How much battery does electric fish machine use?

12V

Calculation: (100 + 99 × 1) + (99 + 99 × 2) + (98 + 99 × 3) + +（2+99×99）+（1+99×100）=______ ．

（100+99×1）+（99+99×2）+（98+99×3）+… +（2+99×99）+（1+99×100）=（100+99+98+97+… 1）+（99×1+99×2+… +99×100）=（100+99… +1）+（100+99+… +1）×99=（100+99… +1) × (99 + 1) = 5050 × 100 = 505000, so the answer is 505000

How much heat can 20 cubic meters of natural gas be released by complete combustion

The low calorific value of natural gas is about 8500Kcal / m3, 20 cubic meters is 8500 * 20 = 170000kcal, equivalent to 711.62mj

When a team of players was trained, all the players moved forward at 35 km / h. Suddenly, the 1 player marched on the speed of 45 km / h, and after 10 km, she turned the car back and still rides back at 45 km / h until she joined the other players. How long time did the 1 players start from the team to meet the players again?

What can electrical energy be converted into? What can be converted into electrical energy

A lot of them
Electric energy is converted into heat energy, such as an electric blanket,
It can be converted into light energy, like electric lights,
Can be converted into chemical energy, such as the charging process of rechargeable batteries
Can be converted into mechanical energy, such as electric cars
.
More energy can be converted into electricity, such as wind energy, water energy, nuclear energy, solar energy, chemical energy (battery), and heat energy from coal combustion