Factorization (1 + AB) ^ 2 + (a-b-2) (a-b + 2Ab)

Factorization (1 + AB) ^ 2 + (a-b-2) (a-b + 2Ab)

Upstairs is the conventional solution, there is another solution to this problem
Note that (a-b-2) (a-b + 2Ab) = (AB + a-b-1) ^ 2 - (1 + AB) ^ 2
Original formula = (1 + AB) ^ 2 + (AB + a-b-1) ^ 2 - (1 + AB) ^ 2
=(ab+a-b-1)^2
=(a-1)^2(b+1)^2

Factorization: given a + B = 5, ab = 3, find the value of (A & # 178; - B & # 178;) &# 178

(a-b)²
=a²+b²-2ab
=(a+b)²-4ab
=5²-4x3
=25-12
=13
(a²-b²)²
=(a+b)²(a-b)²
=25x13
=325

Factorization - AB ^ 3 + 2A ^ 2B ^ 2-A ^ 3B + ABX ^ 2

-ab^3+2a^2b^2-a^3b+abx^2
=-ab(b^2-2ab+a^2-x^2)
=-ab[(a-b)^2-x^2]
=-ab(a-b-x)(a-b+x)

If the absolute value is the same as the opposite number, only if () is the same as the reciprocal number, only if () is the n-th root of 1, only if () is the absolute value equal to the reciprocal number（
All to answer, with the definition, good to give points

Only (0 and negative numbers) have the same absolute value as the opposite number
The only numbers that are the same as the reciprocal are (1 and - 1)
The n-th root of 1 is (1)
The absolute value is equal to the reciprocal only (1)

The method of finding the median of repetition
Take "1,2,3,3,5,6" as an example. First, if there are odd numbers, take the second "3";
Second, the value range of "3" is 2.5-3.5;
Thirdly, because there are three "3", the value range of "3" is divided into three parts: "2.5-2.83", "2.83-3.16", "3.16-3.5";
Fourth, the truth value of the second "3" falls between "2.83-3.16";
Fifth, the estimated value of the second "3" should be (2.83 + 3.16) / 2 = 2.995;
Sixth, the median of this set of data should be "2.995"
The range of 3 'is 2.5-3.5; how does it come from

It doesn't matter if there are repeated numbers. Don't remove them, as long as they are arranged correctly,

When Xiao Ming solved the equation (2x-1) / 3 = (x + a) / 2-1 to remove the denominator, the - 1 on the right side of the equation was not multiplied by 6, so the solution of the equation was x = 2, what was the value of a, and he solved the equation correctly

After general division, the equation is 4x-2 = 3x + 3a-6. Because Xiaoming didn't multiply - 1 by 6, his general division equation becomes 4x-2 = 3x + 3a-1. The value of X he solved should be the solution of the following equation 4x-2 = 3x + 3a-1. Substituting x = 2 into a = 1 / 3

After the Wenchuan earthquake on May 12, 2008, a local civil affairs bureau quickly organized 30 tons of food and 13 tons of clothing for disaster relief. They were ready to be quickly transported to the disaster area by trucks of type A and type B on that night. It is known that each truck of type a can hold 5 tons of food and 1 ton of clothing, and each truck of type B can hold 3 tons of food and 2 tons of clothing. However, due to the rush of time, only one person was recruited (1) three drivers drive type a trucks and six drivers drive type B trucks. Can the relief materials be transported to the disaster area at one time? (2) What kinds of transportation plans are there to transport relief materials to the disaster area at one time?

(1) ∵ 3 × 5 + 6 × 3 = 33 ＞ 30, 3 × 1 + 6 × 2 = 15 ＞ 13, answer: 3 drivers drive type a trucks, 6 drivers drive type B trucks, which can transport disaster relief materials to the disaster area at one time. (2) if there are x type A trucks, then there are 9-x type B trucks

(1) A string of numbers is arranged according to the following rule:
1,3,5,2,4,6,3,5,7,4,6,8,5,7,9,······
From the first number, what is the sum of the first 100 numbers?

The degree sequence contains three arithmetic sequences. The first, the third, the fifth, the seventh 2nd, 4th, 6th, 8th 3, 6, 9, 12 Starting from the first number, add every three numbers, the first 99 numbers get 33 sums: 9, 12, 15, 18 ,105.9+12+15+…… +105 = (9 + 105) × 33 △ 2 = 1881 the number of the first row is the number of the first row

Two thirds of a is equal to one half of B, a: B = (): ()

Number A: number b = (3): (2)

(1) What is the angle between the hour hand and the minute hand at 2:30?
(2) 38 degrees 32 minutes + 15 degrees 46 minutes = how many degrees 37.37 degrees = how many degrees, how many minutes and how many seconds?

(1) At 2:30, the degree of the angle between the hour hand and the minute hand is 120-30 * 1 / 2 = 105 degrees
(2) 54 degrees 18 minutes 0 seconds; 38 degrees 7 minutes 0 seconds