How to solve the equation 2x & # 178; - 4x + 3 √ X & # 178; - 2x + 6 = 15

How to solve the equation 2x & # 178; - 4x + 3 √ X & # 178; - 2x + 6 = 15

√(x^2-2x+6)=t>=0
x^2-2x+6=t^2
x^2-2x=t^2-6
The equation is: 2 (T ^ 2-6) + 3T = 15
2t^2+3t-27=0
(2t+9)(t-3)=0
T = - 4.5 (rounding off) or 3
Therefore: x ^ 2-2x + 6 = t = 9
x^2-2x-3=0
(x-3)(x+1)=0
x=3 or -1

2X & # 178; - 4x-1 = 0 to solve the equation

2x²-4x-1=0
X = 4 ± root (16 + 8) / 4
=4 ± root (24) / 4
=4 ± 2 root number 6 / 4
=(2 ± root 6) / 2

Fourth grade oral arithmetic
Fourth grade volume 1 oral arithmetic

640÷80= 15×5= 23×3=
12×2×5= 480÷80= 16×5=
27×3= 90÷15= 48÷4=
640÷16= 39÷3= 24×20=
32×3= 48÷16= 12×8=
27×3= 56÷14= 24÷8=
14×2= 83－45= 560÷80=
96÷24= 40÷20= 40×30=
37＋26= 76－39= 605＋59=
30×23= 12×8= 27＋32=
48＋27= 4500×20= 73＋15 =
120×600 = 200×360= 6800×400=
280＋270= 4×2500= 6000÷40=
5×1280= 310－70= 400×14=
470＋180= 1000÷25= 160×600=
20×420= 290×300= 8100÷300=
7600÷200= 7600÷400= 680＋270=
980÷14= 4200÷30= 6×1300=
1300×50= 200×48= 930－660=
530＋280= 9200÷400= 840÷21=
180×500= 8000÷500 = 1900÷20=
200×160= 8700÷300= 300×330=
3×1400= 7000÷14= 600÷12=
9600÷80= 140×300= 8800÷40=
9600÷800= 750－290= 5×490=
760×20= 7500÷500= 370×200=
650÷13= 8600－4200= 240×4=
640÷80= 15×10= 12×11=
160×30= 220×40= 104×5=
4500÷50= 20×2= 90÷30=
270÷30= 270×30= 84÷21=
76÷9= 66÷7= 100－54=
23＋15= 360÷4= 55÷5=
32×6= 7000÷70＝ 200÷40＝
180÷30= 240÷40= 35×2=
140×7= 13×6= 280×3=
350×2= 50×11= 250×6=
7200+900= 410-201= 125×8=
48×20= 6600÷600= 390+140=
11×80= 24×50= 3600÷400=
4000÷50= 530－70= 420－90=
9600÷30= 7×700= 203+98=
1800÷300= 240+570= 4800÷400=
370+580= 580－490= 910－370=
420－90＝ 170＋320＝ 1000－51＝
520－260＝ 910－190＝ 35×200＝
22×200＝ 8800÷400＝ 9300÷300＝
6×300＝ 1800÷200＝

The elevator can transport 1.5T goods from the bottom floor to the top of the fourth floor in 10s. If the Mei floor is 3.5m high, what is the power of the elevator?
Take g = 10N / kg

Because of the uniform speed, the work done by the elevator is equal to the gravitational potential energy of the goods. So the power of the elevator is MGH / T, where M = 1500kg, g = 10h = 3.5. So the power of the elevator is 5250w

If the number of items of the arithmetic sequence {an} with tolerance D is odd, A1 = 1, the sum of odd items is 175, and the sum of even items is 150, then D=______ ．

Let the number of terms of arithmetic sequence be 2n + 1, then ∵ A1 = 1, the sum of odd terms is 175, the sum of even terms is 150, ∵ n + 1) · 1 + (n + 1) N2 · 2D = 175n · (1 + D) + n (n − 1) 2 · 2D = 150, ∵ n = 13, d = 4

The vehicle runs at a constant speed of 54 km / h. If the acceleration is 0.5 m / s, the speed after 10 s is?

Conversion v = 54km / h
=54/3.6 m/S
=15m/s
V1=V0＋at
=15＋5=20m/s
=72km/h

Xiaomin and Xiaogang are both stamp collectors. Xiaomin's number of stamps is 34 times that of Xiaogang's. If Xiaogang gives Xiaomin 9 stamps, their number of stamps will be equal. Do you know how many stamps Xiaogang has? (solved by equation)

If Xiaogang has x stamps, Xiaomin will have 34x. According to the meaning of the question, we can get the equation: X-9 = 34x + 9, 14x = 18, & nbsp; X = 72

No matter what the value of K is, x = - 1 is the solution of the equation (KX + a) / 2 = (- x-bk) / 3 about X, then AB is equal to several

The points of + 3 and - 3 on the number axis are on the same side or different side of the origin, and the distance from the origin is unit length
And analyze the meaning of this problem

The points of + 3 and - 3 on the number axis are on the opposite side of the origin, and the distance from the origin is [3] unit length

A mathematical problem, about the distribution of proportion
Divide a pile of sugar among the three children a, B and C. the original plan is that a, B and C will get 5:4:3 candies. In fact, the ratio of candies among a, B and C is 7:6:5. One of them takes 15 more candies. Who is this person? What is his actual number of candies?

According to the original plan, if the number of candies obtained by a, B and C is 5:4:3, then a, B and C are 5 / 12, 4 / 12 and 3 / 12 of the total respectively
In fact, if the ratio of candies a, B and C is 7:6:5, then a, B and C are 7 / 18, 6 / 18 and 5 / 18 of the total respectively
It's obvious that C is more than 5 / 18-3 / 12 = 1 / 36 of the total,
So the total is 15 * 36 = 540
So C should be 540 / 4 = 125
The actual sugar number of C: 540 * 5 / 18 = 150