Mathematics problems and answers on page 180 of Grade 7

No, because the sum of three adjacent columns is 3x (set the number in the middle as x). 40 is not a multiple of 3, so it can't. problem solving 1. Find someone to play by yourself 2. Set the date of the fourth day as X84 = (x-3) + (X-2) + (x-1) + (x + 1) + (x + 2) + (x + 3

RELATED INFORMATIONS

1. The polynomial x ^ 2 + PX + 12 can be decomposed into the product of two first-order factors. The value of integral P is () write two
2. There is a column of numbers: A1, A2, A3 If A1 = 2, then a2007 is () A. 2007B. 2C. 12D. -1
3. Given that a and B are the lengths of two sides of an isosceles triangle, a and B satisfy B 2 + a − 1 + 4 = 4b, the perimeter of the triangle can be obtained
4. If x = 1, y = 6 and x = - 3, y = - 4 are solutions of the equation AX + by + 7 = 0, try to judge whether x = 3, y = 11 are solutions of the equation AX + by + 7 = 0
5. As shown in the figure, the shadow part is a square piece of paper with a side length of 4cm. Cut a small square piece of paper with a side length of 2.5cm in the center of it. Please try to make a rectangle with the simplest method to make its area equal to the area of the shadow part in the figure
6. As shown in the figure, in the quadrilateral ABCD, e and F are the intersection points of two groups of opposite extension lines respectively. Eg and FG divide ∠ BEC and ∠ DFC equally. If ∠ ADC = 60 ° and ∠ ABC = 80 °, then the size of ∠ EGF is () A. 140°B. 130°C. 120°D. 110°
7. 1. As shown in the figure, in a quadrilateral, ab ‖ CD, points E and F are on the sides AD and BC respectively, connecting AC and intersecting EF with G, angle 1 = angle BAC 【1】 Verification of EF ‖ CD 【2】 If ∠ CAF = 15 °, 2 = 45 ° and 3 = 20 °, calculate the degree of ∠ B and ACD 2. As shown in the figure, it is known that AD and AE are respectively the middle line and high line of △ ABC, and ab = 5cm, AC = 3cm. Find the perimeter difference between [1] △ abd and △ ACD 【2】 If BF is the bisector of △ abd, what is the area of s △ BFD? 3. As shown in the figure, it is known that in △ ABC, the bisector of ad bisection ∠ BAC intersects BC at D, ∠ ABC, the bisector of ∠ ACB intersects ad at O, and goes through o to make OE ⊥ BC at E. try to guess the relationship between ∠ BOD and ∠ EOC, and prove your conclusion worry
8. Seventh grade math problems (to process!) 1. Given A-2 + B-3 = 0, find the value of B to the second power of 3AB + 2Ab (the second power of B) - the second power of 4A (the second power of a) 2. If a + B and A-B are opposite numbers, simplify the power of 2008 of a + the power of 2008 of B + the power of 2008 of a - the power of 2008 of B 3. How thick is a piece of paper with a thickness of 0.1 mm if it is folded 20 times? How many floors is it? (to be precise, suppose a floor is three meters high) 4. Known: M = m + m to the power of 2 + m to the power of 3 +... + m to the power of 200 (I) when m = 1, find m; (II) when m = - 1, find m; (III) when M-0, find M 5. If the n-th power of (- 4) is greater than 0 and the m-th power of (- 4) is less than 0, compare the m-th power of (- 1) + (- 1) with the n-th power of 3 + (- 3) 6. A / A + B / B + C / C = - 1, find the value of AB / AB + BC / BC + ABC / ABC To write the process! Well written, give points!
9. 1. Both Party A and Party B set out from a to B at the same time at a speed of 15km / h. When Party A finds that the important goods are placed in a, they immediately return to get the goods and catch up with Party B. if the speed of returning and catching up with Party B is 1.2 times of the original speed, Party B's speed remains unchanged, and both of them reach B at the same time, the distance between two places of AB is calculated 2. When 100 g of 25% sulfuric acid solution is prepared with 50% and 10% sulfuric acid solution, how many g of 50% sulfuric acid solution is prepared?
10. 2（3x-1）²-32=0 27（1-4x）³=125 Find the value of X
11. The area of the rectangle is 6m square + 60m + 150 (M is greater than 0). The ratio of length to width is 3:2. Find the perimeter of the rectangle. This is an application problem
12. 1、（）-3a²+5a-7=-2a²+2a+1 2. If a = x & sup3; - 5x & sup2; - 11x + 6, then A-B = () 3. If the value of the polynomial 3x & sup2; - 2 (5 + y-2x & sup2;) + MX & sup2; has nothing to do with the value of X, then M is equal to X
13. How many seventh grade math problems to solve! Urgent! Is the absolute value of rational numbers If | a | = | B |, then:_____ Or_____ If a + B = 0, then: If | x | = a (a > 0), then x has___ Values, x =______ They are______ Count Simplify 1. a＞1,| a - 1 | 2. a＜1, | a - 1 | 3. x＜2 | x - 2 | 4. x＜ - 3 | x + 3 | 5. -1＜x＜2 6.-1＜x＜2,|x+1|-|x-2| Given | 2 A + 1 | + | B - 2 | + | 3 - C | = 0, find ABC =? Given that | 3 x + 4 | and | 2 x - 1 | are opposite numbers, find x + y =? 5 A + 6 and 2 - A are opposite numbers, so 2A + 3B =?
14. Mathematics problems of grade seven Xiaojie's family bought a new table of 1 or 2 meters. Grandma put two pieces of 1 meter long square cloth together to form a large square cloth. Can you express the side length of the cloth in radical form? Can this cloth cover the table
15. Seventh grade math problems, online speed~~~ As shown in the figure, the triangle ABC is an equilateral triangle, and the point D is the midpoint on the side of BC, which is the degree of ∠ B, ∠ DAC A triangle is isosceles with a vertical bisector in the middle It is known that in triangle ABC, ab = AC, ad bisects ∠ BAC, intersects BC with D, the circumference of triangle ABC is 36, and the circumference of triangle ADC is 30 cm
16. There are strict regulations on the quality of football used in formal football match, and the standard quality is 400g. The following are the quality test results of five football (use positive numbers to record the grams that exceed the specified quality, use negative numbers to record the grams that are less than the specified quality): - 25, + 10, - 20, + 30, + 15. (1) write down the quality of each football; (2) please point out which football has better quality, and use the absolute value We can judge by our knowledge
17. For any natural number n, we can prove that (n power of 3, n power of 4) = (3,4). The proof is as follows: let (n power of 3, n power of 4) = x, then NX power of 3 = n power of 4, i.e. (n power of X power of 3), so x power of 3 = 4, i.e. (3,4) = X, Thus (n-th power of 3, n-th power of 4) = (3,4). (1) according to the above provisions, (3,27) = (5,1) = (2) explain the reason why equation (3,4) + (3,5) = (3,20) holds
18. Make up a practical problem according to the requirement and answer your practical problem The writing requirements are as follows: 1. To write an applied problem of downstream and downstream water, so that the equation listed according to the meaning of the problem is 9 (x + 2) = 11 (X-2) 2. The structure of the applied problem is complete, the meaning of the problem is clear, and it is in line with the reality
19. Seventh grade math problems and answers Thank you
20. 1. If A2 + ab-2b2 = 0 and B ≠ 0, find the value of (2a-b) / (2a + b) 2. A + B = 1, find the value of A3 + B3 + 3AB