Given the algebraic formula 14x + 5-21x ^ = - 2, it is faster to find the value of 6x ^ - 4x + 5

Given the algebraic formula 14x + 5-21x ^ = - 2, it is faster to find the value of 6x ^ - 4x + 5

14x+5-21x^=-2,
21X^2-14X-7=0
3X^2-2X-1=0 ==>3X^2-2X=1
6x^-4x+5=2(3X^2-2X)+5=1*2+5=7

The known algebraic formula 14x + 5-21x 2 = - 9, find the value of 6x 2-4x-5

-1

The square of a + 3b and 2B (a + b) (a not equal to b) (x + 1) and X4 + X2 - 2x (x not equal to - 1) compare the size of two algebraic formulas

a²+3b²-2b(a+b)
=a²+3b²-2ab-2b²
=a²-2ab+b²
=(a-b)²
∵a≠b∴(a-b)²>0
∴a²+3b²-2b(a+b)>0
∴a²+3b²>2b(a+b)
(2)
（x²+1)²-(x⁴+x²-2x)
=x⁴+2x²+1-x⁴-x²+2x
=x²+2x+1
=(x+1)²
∵ x is not equal to - 1
∴(x+1)²>0
∴
（x²+1)²>x⁴+x²-2x

-(x2 + 3x) + 2 (4x + x2), where x = - 2

The original formula = - x2-3x + 8x + 2x2 = x2 + 5x, when x = - 2, the original formula = 4 + 5 × (- 2) = - 6

There are six yellow balls and several white balls in the pocket. They are all the same except for the color. If the possibility of finding out a yellow ball is 34, the white ball in the pocket is 34______ One

6 △ 34-6 = 8-6, = 2 (pieces). Answer: there are 2 white balls

How many square meters is 3.3 hectares

One hectare = 1 oooo square meter
3.3 ha = 33000 M2

Monkey Sun eats peaches -- () allegorical sayings Fan Jin's mid rise -- () rotten net fishing -- () monkey eats pepper -- () rotten hat edge -- ()

The answer to the first question on page 23 of the Chinese winter vacation homework for Grade 5 of primary school is:
Monkey Sun eats peaches
Fan Jin's Zhongju
Fishing in a rotten net
Monkeys eat chili
The hat has a rotten edge

Several chemistry calculation problems in the first semester of grade nine
Please write the steps in detail (including chemical formula, calculation, etc.) thank you
1. There is a mixture of magnesium powder and magnesium oxide powder. The mass fraction of oxygen in the mixture is 32%
2. Weigh a few grams of dilute sulfuric acid with a certain mass fraction of 20%, mix them, and react completely to produce 0.1g hydrogen
(1) Weigh the mass of zinc powder as () g. ← and write down the steps,
(2) Total mass of solution after reaction
3. Pass the mixture of carbon dioxide and carbon monoxide into the excess clarified lime water, and measure every 10g of this mixture
The mass fraction of carbon monoxide in the mixed gas can be calculated

1. In magnesium oxide, the mass ratio of oxygen to magnesium is 24:16, so there is 24:16 = x: 32% X is the mass fraction of magnesium in the mixture, and the solution is x = 48%, so the mass fraction of magnesium powder is 1-32% - 48% = 20%

70000 cubic centimeter = () cubic decimeter?

70

Mathematics test paper for the second semester of the sixth year of Jiangsu Education Press (4)
1、 Xiaohua walks 50 meters, 79 steps for the first time, 80 steps for the second time and 81 steps for the third time. The average distance of one step is about () meters. He walks 1200 steps from home to school, and the distance between his home and school is about () meters
2、 A precision part is 2mm long and 4cm long when drawn on a drawing. The scale of this drawing is ()
3、 If the radius of the bottom of the cylinder is twice that of the cone and the height of the cone is twice that of the cylinder, then the volume relationship between the two objects is () choice
1. The volume of cylinder is larger than that of cone
2. The volume of cylinder is smaller than that of cone
3. The volume of a cylinder is equal to that of a cone
4. Not sure
4、 64% has been completed. It's the process diagram of Mr. Liu's downloading a file on the computer. The computer shows that it takes 25 minutes to download the file, so how many minutes does Mr. Liu have to wait to download the file?
5、 Uncle Wang bought a car worth 167800 yuan. According to the regulations, he has to pay 10% vehicle purchase tax to buy a bicycle. How much does Uncle Wang spend on the car
6、 Assign a batch of parts to Party A and Party B according to the ratio of 4:5. Party A has actually made 480 parts, more than 40 of the assigned tasks. How many parts has Party B actually made
7、 A cylindrical timber is 2 meters long. According to the section of 5 decimeters, the surface area of the remaining timber is 94.2 square decimeters less than that of the original timber

1、50×3÷（79+80+81）×12000=750
2. Scale = distance on the map: distance of real object = 40:2 = 20:1
3. Choose 1, cylinder volume = π R ^ 2h, cone volume = 1 / 3 π R ^ 2H
R=2r,H=1/2h,
Cylinder volume = π (2R) ^ 2 × 1 / 2H = 2 π R ^ 2H > cone volume = 1 / 3 π R ^ 2H
4、25×（1-64%）=9
5、167800×（1+10%）=184580
6、（480-40）÷4×5-40=510
7. The remaining area is 94.2 square decimeters less than the surface area of raw wood, which is exactly the side area of 5 decimeters
The radius of the bottom surface of this wood: 94.2 ÷ (5 × 2 π) = 3,
The volume of this wood: π 3 ^ 2 × 20 = 565.2