Xiaojun had three times as many storybooks as Xiaoli. Xiaojun bought seven more. After Xiaoli bought six, Xiaojun had two times as many books as Xiaoli How many books? Use equations to solve it

Xiaojun had three times as many storybooks as Xiaoli. Xiaojun bought seven more. After Xiaoli bought six, Xiaojun had two times as many books as Xiaoli How many books? Use equations to solve it

Xiaoli (6 × 2-7) / (3-2) = 5 books
Xiaojun 5 × 3 = 15

Teacher, I'll ask you another question: ad is the middle line on the side BC of the triangle ABC, ab = BC, and ad divides the perimeter of the triangle ABC into three and four parts to find AC
Ad is the middle line on the side BC of the triangle ABC, ab = BC, and ad divides the perimeter of the triangle ABC into three and four parts to find the length of the side AC,

Let BD = CD = x, AC = y, then AB = BC = 2x, there are 3x = 3 or 3x = 4, corresponding to x + y = 4 or 3, the solution is: x = 1, y = 3 or x = 4 / 3, y = 5 / 3

The greatest common divisor of two numbers is 8, the least common multiple is 48, one of them is 16, what is the other number?

48 △ 16 = 33 × 8 = 24 A: another number is 24

A geometric problem is known that the circumference of △ ABC is 36cm, A.B.C is the length of triangle trilateral, and a + B = 2c, B = 2A. Find the value of a.b.c

Substituting B = 2A into a + B = 2c, we get a + 2A = 2c, that is, 3A = 2c, C = 1.5A,
Since the circumference of the triangle is 36, then a + B + C = 36,
So, a + 2A + 1.5A = 36
4.5a=36
a=8
b=2a=16,c=1.5a=12
So, a = 8, B = 16, C = 12

What are all odd numbers? What are even numbers? What are prime numbers? What are total numbers?

Within 100:
Odd numbers: 1,3,5,7,9,11,13,15,17,19,21,23,25,27,29,31,33,35,37,39,41,43,45,47,49,51,53,55,57,59,61,63,65,67,69,71,73,75,77,79,81,83,85,87,89,91,93,95,97,99
Even numbers: 2,4,6,8,10,12,14,16,18,20,22,24,26,28,30,32,34,36,38,40,42,44,46,48,50,52,54,56,58,60,62,64,66,68,70,72,74,76,78,80,82,84,86,88,90,92,94,96,98100
Prime numbers: 2,3,5,7,11,13,17,19,23,29,31,37,41,43,47,53,59,61,67,71,73,79,83,89,97
Total number: 4,6,8,9,10,12,14,15,16,18,20,21,22,24,25,26,27,28,30,32,33,34,35,36,38,39,40,42,44,45,46,48,49,50,51,52,54,55,56,57,58,60,62,63,64,65,66,68,69,70,72,74,75,76,77,78,80,81,82,84,85,86,87,88,90,91,92,93,94,95,96,98,99100

As shown in the figure, the graph of the linear function Y1 = K1X + B1 and y2 = k2x + B2 intersects a (3,2), then the solution set of inequality (k2-k1) x + b2-b1 > 0 is______ ．

It is known from the graph that when x ＜ 3, Y1 ＜ Y2, that is, y2-y1 ＞ 0; when x ＜ 3, k2x + B2 - (K1X + B1) ＞ 0; it is reduced to: (k2-k1) x + b2-b1 ＞ 0; therefore, the solution set of the inequality is: x ＜ 3

Is the square of complex Z equal to the square of Module Z?

Unequal
Square of complex number: z = a + bi Z ^ 2 = a ^ 2 + 2abi-b ^ 2
Square of complex modulus: z = a + bi | Z | ^ 2 = a ^ 2 + B ^ 2

The parabola y = ax + BX + C passes through point (0, - 1) and point (3,2), and the vertex is on y = 3x-3, a < 0. Find the analytic expression of this function

If passing through point (0, - 1), then C = - 1, passing through point (3,2), then 9A + 3b-1 = 2, that is, B = 1-3a, vertex is (- B / 2a, - 1-B ^ 2 / 4A) on the line y = 3x-3, vertex substitution is: - 1-B ^ 2 / 4A = - 3B / 2a-3, and B ^ 2 = 6B + 8A substitution is b = 1-3a: 1-6a + 9A ^ 2 = 6-18a + 8a9a ^ 2 + 4a-5 = 0 (9a-5) (a + 1) = 0, because a

The following judgment is correct ()
A. There are two triangle congruences with two opposite angles and one of them equal B. There are two isosceles triangle congruences with two opposite angles and one angle of 30 ° C. There are two right triangle congruences with one angle and one side equal d. There are two triangle congruences with two angles and one side equal

A. Only when two triangles are acute triangle, obtuse triangle or right triangle, can it be established; B. If 30 ° angle has no corresponding relationship, it can't be established; C. If this angle is right angle, it won't be established; D. judgment method of congruent triangle: AAS or ASA. So D

Given the function f (x) = x ^ 3-ax ^ 2-A ^ 2x + 1 g (x) = 1-4x-ax ^ 2, where real number a ≠ 0, find the monotone interval of function f (x)
Ask for detailed explanation

Why do you write g (x) when you ask f (x)?
Because f '(x) = 3x ^ 2-2ax-a ^ 2 = (x-a) (3x + a)
When a > 0, Let f '(x) > 0, then x > A or x0, then x > - A / 3 or X