Xiaohua plans to read a 120 page story book in [7 days] a week. On the first day, he reads 1 / 5 of the book, and the rest 16 pages a day. Can he finish it in the original time

Xiaohua plans to read a 120 page story book in [7 days] a week. On the first day, he reads 1 / 5 of the book, and the rest 16 pages a day. Can he finish it in the original time

The first day: 120 * 1 / 5 = 24 (page) 120-24 = 90 (page) 16 * 6 = 96 (page) 96 more than 90 pages
A: he can finish it in the original time

Xiao Gang has eight pictures, twice as many as Xiao Li's and Xiao Ming's. how many pictures do they have?

This is Xiaoli
8 × 2 = 16. This is Xiao Ming
8+4+16=28

Xiao Gang and Xiao Ming have a total of 220 pictures. Xiao Ming has three times as many as Xiao Gang and 20 more. How many pictures do Xiao Gang and Xiao Ming have?

Suppose Xiaogang has x and Xiaoming has y, and then make the equation: x + y = 220; 3x + 20 = y. it is concluded that x = 50 and y = 170, that is, Xiaogang has 50 and Xiaoming has 170

It is proved that the value of the algebraic formula 2x2-x + 3 is not less than 238

Prove: 2x2-x + 3 = 2 (x2-12x + 116) - 18 + 3, = 2 (x − 14) 2 + 238 ≥ 238, then prove that the value of the algebraic formula 2x2-x + 3 is not less than 238

What is the reciprocal of 5 / 6 of a number to 11 / 12

Let this number be X
5/6x=12/11
X = 72 / 55 this number is 72 / 55
The reciprocal of this number is 55 / 72

How to substitute 2x-3y = 0 3x + 4Y-2 = 0 into elimination? And 3x + 4Y = 18 2x-3y = - 5

2x=3y
x=3y/2
Substituting it into equation 2, we get
3*3y/2+4y-2=0
How to solve the equation
y=17/4
Substituting equation 1, we get
x=51/8

It is known that function f (x) always has f (x + y) = f (x) + F (y) for any real number x, y, and if x > 0, f (x) < 0. And f (1) = - 2. (1) judge the parity of function f (x); (2) find the maximum value of function f (x) in the interval [- 3, 3]; (3) solve the inequality f (AX2) - 2F (x) < f (AX) + 4

(1) Let x = y = 0, then f (0 + 0) = 2F (0), 〈 f (0) = 0 Let 1 ′ be y = - x, then f (x-x) = f (x) + F (- x) ‖ f (- x) = - f (x) is an odd function for any x ∈ R 3 ′ (2) if x 1, x 2 ∈ (- ∞, + ∞) and x 1 ＜ x 2, then x 2-x 1 ＞ 0, f (x 2) + F

Is x (x – 3) a fraction

Yes, knowledge is replaced by symbols

If the two vertices of the parabola y = ax ^ 2 + BX + 3 and - x ^ 2 + 4x + 2 are symmetric about the origin, the values of a and B are obtained

The vertex coordinates of y = AX2 + BX + 3: (- B / 2a, 12a-b2 / 4A); the corresponding vertex of y = - x2 + 4x + 2 is (2,6)
b/2a=2,b2-12a/4a=6；
The solution is a = 2 / 3, B = 6;

/X-3/-/X-1/

The zero segment method is to divide the number axis into several segments with the zero point of the function and discuss the problem step by step. For example, in this problem, the number axis is divided into three segments with x = 1 and x = 3
(1).x