If you encounter a problem, ask the math master to help solve it

You misunderstand the ratio here.

Division. meaning.

For example. a b = c d = k (k is a constant).

is a proportional relationship.

k=c÷d=a÷b

If a b c = d e f = m (m is a constant).

Here it is indicated. And. cd

e} is proportional, and m is its minimum. Determinant.

proportional. m=

Maybe the contemptible can do a little bit! (1) The dual formula cos36°cos72° sets x=cos36°y=72° from cos72°=2(cos36°) 2 1 to get y=2x 2 1, and from cos36°=1 2sin(18°) 2=1 2cos(72°) 2 then x=1 2y 2, then x

y=2(xy) (x y) and because of x

y is not equal to 0=》x y=1 2, i.e. cos36° cos72°=1 2(2) is derived from the title, and the points (a, b) are in the ellipse a 2 6

b 2 3 = 1, then the parametric equation of the ellipse gives a = root number 6 times cos@, b = root number 3sin@ (@为参数) then a root number.

When there are more than three consecutive ratios, it is not possible to simply equal the ratio sign to the division sign, for example, 1:2=1 2, 2:4=2 4=1 2 (here the ratio sign is equal to the division sign), and 1:2:3 if the ratio sign is equal to the division sign, it is equivalent to (1 2) 3

And 2:4:6 is equivalent to (2 4) 6 = (1 2) 6

One of the two ratios is 1 2 divided by 3, and the other is 1 2 divided by 6, so the ratio sign can no longer be equated with the division sign, even if it is to be equal, it can only be divided from the order of four operations, and when there are no parentheses, it is divided from left to right in turn.

2:4:6=1:2:3=1 6, is not equal to 2 4 6, the ratio can be simplified, equivalent to dividing by the common divisor.

Answer socks and cover the case and choose C! ** after the first price reduction is a*(1-10%)=

The first day of the second state price is **.

After the price increase, ** is.

The original rough key auction price of a commodity is a yuan, and after the price is reduced by 10%, it is Yanxian A* (1-10%)=, and it is reduced by 10% on the original basis.

The price is increased by 20%, and the ** of this commodity is after the price increase.

Choose co( bright stove ) o thank you ·

The speed of the first workshop is 1 30, and the speed of the second workshop is 1 201.

1 30) x + (1 20) (25-x) = 1 to get x = 15

2. Set the equation that takes x days to column.

1 30)*3+(1 30+1 20)x=1 gets x=

Mengmeng: 50 10 3 = 15m

Fangfang: (50-15) 7 3=15m

Total left: 50-15-15=20m

I'm a "person who has come over", don't believe the answer, we used to do a lot of fooling people.

It will also be known by the teacher that it is the ...... who has read the answer

Meng Meng used 50 * 3/10 = 15 meters, the remaining 50-15 = 35 meters, Fang Fang used: 35 * 3/7 = 15 meters, so there is still 35 - 15 = 20 meters.

The answer should be 20 meters. The 50-meter-long cloth, Mengmeng used three-tenths, and there were seven-tenths left, that is, 35 meters left, and Fangfang used the remaining three-sevenths, and there were four-sevenths left, that is, 35*(4 7)=20 meters. The last remaining should be 20 meters.

Meng used 15 meters, Fangfang used 35 * three-sevenths = 20 result = 15 your answer is wrong??? Or maybe you're wrong.

Math is 92*3-(92-2)*2=96

English is 90+ languages.

Mathematics + Chinese + English = 92x3 = 276

Chinese + English = 90x2 = 180

So: Mathematics = 276-180 = 96 points.

Chinese + English = 180

English-language = 3

Lide Language: English.

Solution, let's: number, language, and English are x, y, z

x+y+z=92*3

z-y=392-(y+z)/2=2

Solution: x=88

y=z=

Let math be x, language y, and English z

x+y+z=276

y+z=180

z-y=3x=96；y=；z=

Suppose the book has x pages.

By the title, read x 10 pages in the morning.

Column equation: x 10 + x 10 + 6 = x 4

x=120

So the book is 120 pages long.

Thank you! The first floor was done wrong.

In the morning, the ratio of the number of pages read to the number of unread pages is 1:9, so the number of unread pages is 9 10 of the total number of pages, the ratio of the number of pages read to the number of unread pages in the afternoon becomes 1:3, and the number of unread pages accounts for 3 4 of the total, let the total number be x, and in the afternoon read x 10 + 6, x 10 + 6 = 9 10-3 4, x = 120

The book is 120 pages long.

The total number of pages of the book has not changed:

Morning: Read: Unread = 1:9 = 2:18

Afternoon: Read: Unread = 1:3=5:15

If you have read 5 copies in the afternoon and 2 copies in the morning, then read 3 copies in the afternoon, 1 more copy than in the morning: 6 (5-2-2) = 6 (pages).

The book has: 6x(2+18)=120 (pages).

In the morning, I read 1 (1+9)=1 10 of the whole book

In the afternoon, I read 1 (1+3)=1 4 of the whole book

I read 6 pages in the afternoon.

A: The book is 40 pages long.

The total number of pages remains the same.

The morning reading is the total: 1 (1+9)=1 10 The afternoon reading is the total: 1 (1+3)=1 4

I read more in the afternoon than in the morning: 1 4-1 10=3 20 The total number of pages is: 6 (3 20)=40 (pages).

Solution: I read x pages in the morning, according to the title, there is.

I read (x+6) pages in the afternoon, because when I read part of it in the morning, the ratio of the number of pages read to the number of unread pages is 1:9, so the whole book has 10x pages.

x=4, so the whole book has 10x=10*4=40 pages.

Give me extra points, thank you.

Before reading 6 pages, the pages read accounted for 1 (1+9)=1 10 After reading 6 pages, the pages read accounted for 1 (1+3)=1 4, so the proportion of 6 pages in the whole book was 1 4-1 10=3 20, so the whole book has:

6 (3 20) = 40 pages.

If the number of pages of the book is x, then the number of pages read in the morning is, the number of unread pages is, the number of pages read in the afternoon is, the number of pages read is, and the number of pages not read is, and x=120 can be obtained by solving the equation by the title (

Let the number of pages read in the morning be y, and the total number of pages is x

y：x-y=1:9

2y+6：x-2y-6=1:3

x=120

In the picture on the right, there is a problem at the junction of A and D.

The slope of the hypotenuse of D is 2 5, the slope of the section of the hypotenuse of A and the section of the section that does not meet Ding is 1 3, and the overall slope of the whole hypotenuse of A is 3 8

That is, the hypotenuse of A is not a straight line.

Hope mine is helpful to you!

In fact, the figure that appears to be a right triangle formed by B and D is not a triangle, and its hypotenuse is not a straight line. Therefore, the whole figure is not rectangular either.

Odd function, f(0)=0, get (b-1) This celery(1+a)=0, that is, b=1, f(-1)=-f(1), get the branch balance: a=1

f(t 2-2t)<-f(2t 2-k) = f(k-2t 2), and the subtractive function has t 2-2t>k-2t 2 constant.

Therefore, 3t 2-2t-k>0 is always established, so the senda discriminant < 0,4-12k<0,k>1 3

Solution: (1) f(x) is an odd function, and the domain is defined as r, Lie bureau f(0)=0(b-2 0) rock slip (a+2 0) =b-1) (a+1)=0 b-1=0 so b=1f(x)=(1-2 x) (a+2 x) and f(-x)=-f(x) 1-2 (-x)] a+2 (-x)]=2 x-1) (a+2 x) (the left numerator and denominator are multiplied by 2 x) 2 x-1) (a*2 x+1)=(2 x-1) (a+2 x) i.e. a* 2 x+1=a+2 x a*2 x-a=2 x-1 a*(2 x-1)=2 x-1 a=1

2）f(t^2-2t)<-f(2t^2-k)f(t^2-2t)k-2t^2

That is, for everything T r has: 3t 2-2t-k>0b 2-4ac=4+12k<0

k<-1/3