10 different Chinese books, 2 different mathematics books, from which randomly take out 2, can take out the probability of mathematics books?

10 different Chinese books, 2 different mathematics books, from which randomly take out 2, can take out the probability of mathematics books?

According to the meaning of the title, take out the mathematics book as event a, then the opposite event is to take out all the Chinese books. Take out 2 of 12 books randomly from 10 different Chinese books and 2 different mathematics books, there are c122 = 66 cases, if all the Chinese books are taken out, there are C102 = 45 cases; then p (. A) = 4566 = 1522, P (a) = 1-1522 = 722. So the probability of taking out the mathematics book is 722

There are four different Chinese books and two different mathematics books. Now take out two of them randomly. What's the probability of getting mathematics books

1-4/6*3/5=3/5

Eight different Chinese books and three different mathematics books. What's the probability of taking two out of them?

The probability that both books are mathematics books is as follows:
C(3,2)/C(11,2) *100=(3/2)/(11*10/2) * 100 =2.73%

I am 12 years old,

I'm 12 years old.
I like Chinese very much.

How to calculate x ^ 2 + 5x + 6 of x ^ 2 + 5x + 5 minus x ^ 2 + 8x + 15 of x ^ 2 + 8x + 14

The original formula = (x ^ 2 + 5x + 6 -- 1) / (x ^ 2 + 5x + 6) - (x ^ 2 + 8x + 15 -- 1) / (x ^ 2 + 8x + 15) = 1 -- 1 / (x ^ 2 + 5x + 6) -- 1 + 1 / (x ^ 2 + 8x + 16) = 1 / (x ^ 2 + 8x + 16) -- 1 / (x ^ 2 + 5x + 6) = [(x ^ 2 + 5x + 6) - (x ^ 2 + 8x + 16)] / (x ^ 2 + 8x + 16) (x ^ 2 + 5x + 6) = -- (3x + 10) / ((x ^ 2 + 8x + 16) (x ^ 2 + 5x + 6)

Is it wrong that 1 cm on the plan scale of 1:50 indicates the actual distance of 50 meters?

The scale is 1:50, 1 cm on the plan represents the actual distance of 50 meters (wrong)
1 cm is the actual distance of 50 cm

Look at the following equation (where "!" Is a mathematical operation symbol) 1! =1，2！ =2×1，3！ =3×2×1，4！ =4×3×2×1，… , calculate 100! 98=______ ．

100!98!=100×99×98×… ×198×97×96×… ×1=100×99=9900．

How to convert gram weight per meter into gram weight per square meter

1 square meter = 1 meter x 1 meter
1 m x fabric width per meter
Divide up and down, and multiply the number by the actual gram

Calculate the shaded area of the figure below (in centimeters)

=2×(3.14×4²/4-4×4/2)
=2×(12.56-8)
=9.12
Equal to the area of two arches
An arch is equal to the area of a quarter circle - the area of a triangle

Which animals are axisymmetric in life
A little more, I want animal names!

Butterflies, dragonflies and so on. As long as the middle is folded in half, what can cover each other is axisymmetric. There are crabs, spiders, ants, bats, eagles. Almost all animals are, only those with deformities are not