The total price of 80 Chinese books and 100 mathematics books is equal. It is known that each Chinese book is 5 jiao more expensive than the American mathematics book

The total price of 80 Chinese books and 100 mathematics books is equal. It is known that each Chinese book is 5 jiao more expensive than the American mathematics book

Set X Yuan for mathematics books and X + 0.5 yuan for Chinese books
80（X+0.5）=100X
X=2
Chinese book price: 2 + 0.5 = 2.5 (yuan)

The total price of 80 Chinese books and 100 mathematics books is equal. It is known that each Chinese book costs 2.5 yuan more than each mathematics book. How much is the unit price of Chinese books and mathematics books
We should make assumptions

If the unit price of Chinese books is X Yuan and that of mathematics books is y yuan, and the total price of 80 Chinese books and 100 mathematics books is equal, then 80x = 100y. Each Chinese book costs 2.5 yuan more than each mathematics book, x = 2.5 + y. the solution is x = 12.5 and Y = 10

The relation of quadratic function ABC

The combination of number and shape
(1) A determines the opening direction of the function image
(2) C is the ordinate of the intersection of the function image and the y-axis, that is, the y-axis intercept
(3) The discriminant $= B ^ 2-4ac determines the number of solutions of the equation, that is, the number of intersections between the function image and the x-axis
(4) - B / 2a is the abscissa of the axis of symmetry of the function image

5 × 9 5.55 × 9 5.555 × 9

5.5×9=49.5
5.55×9=49.95
5.555×9=49.995
therefore
5.5555×9=49.9995
5.55555×9=49.99995
5.555555×9=49.999995

Given that the domain of definition of function f (x) = 1 / log2 (3x-2) is set a, the solution set of inequality 1 / 2-x is r, (1) find (CUA) ∩ B (2) denote a ∪ B = C

The domain of F (x) = 1 / log2 (3x-2) is 3x-2 > 0, x > 2 / 3
Set a = {x | x > 2 / 3}
The solution set of inequality 1 / 2-x is r

How easy is it to multiply 38 by 101 and subtract 38

38 times 101 minus 38
=38*(101-1)
=38*100
=3800

(1) If 3x-5 and 1-x are the square root of a number, then the value of X is 3 times of (2) x, and the difference between X and 2 is a non positive number, that is, the inequality is

That is, 3x-5 and 1-x are opposite numbers
So 3x-5 = X-1
2x=4
x=2
Non positive numbers are zero and negative numbers
So 3x-2 ≤ 0

If Tan (a + Wu / 4) = 2, what is 1-cos2a / sin2a equal to

Do you mean (1-cos2a) / sin2a? Or 1 - (cos2a / sin2a)? Tan (a + b) = (Tana + tanb) / (1-tanatanb) Tan (a + Wu / 4) = (Tana + Tan / 4) / (1-tana * Tan / 4) = (Tana + 1) / (1-tana) = 2, so Tana = 1 / 3cos2a = 2 (COSA) ^ 2-1 (1-cos2a) / sin

For the equation 2x ^ + 3x-5m = 0 of X, there are two real roots less than 1, and the value range of M is obtained
Don't use the method of axis of symmetry. If you want to use it, you'd better use other methods

A range of M is obtained when △ 0
Let two X 1 and x 2 find out the range of m according to Weida's theorem (x 1-1) + (x 2-1) < 0 & nbsp; (x 1-1) * (x 2-1) > 0
&The last two ranges intersect
&Do it yourself & nbsp;
    

Simple calculation of 32 × (71-54)
thank

(30+2)*17=510+34=544
Is that easy enough