There are 120 ~ 160 books in the book corner, one fifth of which are comic books and one seventh are story books. How many books are there in the book corner

There are 120 ~ 160 books in the book corner, one fifth of which are comic books and one seventh are story books. How many books are there in the book corner

one hundred and forty

There are 56 story books, 32 science and technology books and 38 comic books in the book corner of class 5-3. How many of these books are story books

56/(56+32+38)=28/63

There are 60 comic books in class 6-2, of which 3 / 2 are story books. The ratio of story books to science and technology books is 2:9. How many are science and technology books?

60x3 / 2 △ 2 / 9 = 405 copies

Given the exponential function y = (2a2-5a + 3) ax power, find the maximum and minimum of F (x) on [0, a]

∵ y = (2a2-5a + 3) ax is an exponential function ∵ 2a2-5a + 3 = 1 ∵ 2a2-5a + 2 = 0. The solution is a = 1 / 2 or a = 2. If a = 1 / 2, f (x) = (1 / 2) ^ x is a decreasing function on [0,1 / 2] ∵ f (x) min = f (1 / 2) = √ 2 / 2F (x) max = f (0) = 1. If a = 2, f (x) = 2 ^ x is an increasing function on [0,2] ∵ f (x) min = f (0) = 1F (x) max = F

How to calculate (15 / 56-13 / 42 + 11 / 30-9 / 20 + 7 / 12-1 / 3) △ 1 / 22 × 91 △ 1 / 8?
emergency

(15 / 56-13 / 42 + 11 / 30-9 / 20 + 7 / 12-1 / 3) △ 1 / 22 × 91 △ 1 / 8 = (1 / 7 + 1 / 8-1 / 7-1 / 6 + 1 / 6 + 1 / 5-1 / 5-1 / 4 + 1 / 3-1 / 3) = 1 / 8 △ 1 / 22 * 91 △ 1 / 8 = 91 / 22 = 3 / 4

If the point (2, m) is on the curve X & # 178; - xy-2y = 4, then the value of M is

According to the meaning of the question, the point is substituted into the equation
4-2m-2m=4
So - 4m = 0,
That is, M = 0

If the inequality x2-ax + 1 > 0 holds for all positive numbers x, the value range of a is obtained

x²-ax+1>0
x²+1>ax
Because x > 0, so
(x²+1)/x>a
If A0 is constant, then a must be less than the minimum value of formula x + (1 / x)
From the mean inequality, x + (1 / x) ≥ 2 √ [x (1 / x)] = √ 2
That is, the minimum value of X + (1 / x) is √ 2
So the value range of real number a is a

20 questions of vertical calculation

15x14 567÷7 11x99 897÷5 698x67 78x700 6754÷67
458÷8 86x895 679÷81 784x75 75x78 11x11 98x57
748x14 678÷5 988x2 976x12

The calculation limit limx → 1 (11 − X-31 − x3)

The original formula = limx → 1x2 + X − 2 (1 − x) (1 + X + x2) = - limx → 1 & nbsp; X + 21 + X + x2 = - 1

5x + 2Y = 12 4x-3y = 5 substitution method to solve binary linear equation to help 6 p.m. arcane class

Hello
5x+2y=12
2y=12-5x
y=6-2.5x
4x-3(6-2.5x)=5
4x-18+7.5x=5
4x+7.5x=5+18
11.5x=23
x=2
y=6-2.5x2=1
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