A is x, B is y, the difference between the squares of a and B

A is x, B is y, the difference between the squares of a and B

x^2 - y^2
=(x+y)(x-y)

If the cube of B is one eight and the square of a is 25, what is the sum of a and B?

The cube of number B is one eight, and the square of number a is 25
B: - 2, a: ± 5
-2 ± 5 = 3 or - 7
The sum of a and B is 3 or - 7

What is the sum of four times of a and the opposite number of B? The sum of squares of a and B? The sum of squares of a and B?

1.4 a-b
2. A-178; + b-178;
3. (a + b) &;

The difference between the two numbers is 2, and the sum of squares is 52

4,6 or - 4, - 6

If the difference is 3 and the sum of squares is 65, then the two numbers are?

7,4

a. B, C are positive integers, and (√ 3A + b) / (√ 3B + C) are rational numbers. Find the value of (a + B + C) / (a + B + C)

(√ 3A + b) (√ 3b-c) / (3b ^ 2-C ^ 2) = [3AB BC + √ 3 (- AC + B ^ 2)] / (3b ^ 2-C ^ 2), (√ 3A + b) / (√ 3B + C) is a rational number, AC = b ^ 2, a, B, C is a proportional sequence. (a + B + C) / (a + B + C) = A-B + C

The following group of numbers 1 5 13 25 41 are known to represent the nth number with algebraic expression

(n-1)^2+n^2

If n (n + 1) is the nth term of a group of numbers in regular order, then the 10th term of the group of numbers is n (n + 1)______ If the number of a group is 2,6, - 12,20,30, - 42,56,72, - 90 Then the 3nth term of this group of numbers is______ ．

∵ the nth term is n (n + 1) ∵ the 10th term = 10 × (10 + 1) = 110 ∵ 2 = 1 × 2; 6 = 2 × 3; - 12 = - (3 × 4); 20 = 4 × 5; 30 = 5 × 6; - 42 = - (6 × 7) The rule is: n (n + 1), and the third term and its multiple term are negative. ∵ 3N is the multiple of 3, so the 3N term is negative ∵ 3N = - 3N (3N + 1)

It is known that: a column of numbers - 3,5 / 2,1,9 / 14,11 / 23. The nth number is represented by an algebraic expression containing the letter n?

Analysis: first look at the molecule. The second one is 5. The fourth one is 9. The fifth one is 11. Obviously, the nth numeral molecule is 2n + 1. So write - 3 / - 1.1 as 7 / 7. It can be found that - 1 = 1 & # 178; - 2.2 = 2 & # 178; - 2.7 = 3 & # 178; - 2. Then the nth numeral denominator = n & # 178; - 2. So the nth numeral is (2n + 1) / N & # 178; - 2

-1,3,-5,7,-9,11…… Expressed by an algebraic expression containing n

an=(-1)^n*(2n-1)