The first year of junior high school merges the same category 5 (x + y) third power-2 (X-Y) fourth power-2 + (Y-X) fourth power Today's assignment of the high school attached to the National People's Congress is a little difficult,

The first year of junior high school merges the same category 5 (x + y) third power-2 (X-Y) fourth power-2 + (Y-X) fourth power Today's assignment of the high school attached to the National People's Congress is a little difficult,

5 (x + y) cubic-2 (X-Y) quartic-2 + (Y-X) quartic
=5 (x + y) cubic-2 (X-Y) quartic + (X-Y) quartic-2
=5 (x + y) cubic - (X-Y) quartic-2

3 (X-Y) ^ 2-7 (X-Y) + 8 (Y-X) ^ 2 + 6 (Y-X) merge similar items

(11(x-y)-13)(x-y)

The square of (x + y) is known to be 7, and the square of (X-Y) is known to be 3

x²+2xy+y²=7
x²-2xy+y²=3
subtract
4xy=4
xy=1
Add
2(x²+y²)=10
x²+y²=5
square
x^4+2x²y²+y^4=25
x^4+y^4=25-2(xy)²=23
x^6+y^6
=(x²+y²)(x^4-x²y²+y²)
=5×(23-1²)
=110

X-Y = - 3 x + y = 7 find the square of X + the square of Y

X = 3 + y, bring it into x + y = 7
That is, 3 + y + y = 7, y = 5 and X-Y = 3
That is, X-5 = 3, x = 8
So the square of X + the square of y = x times x + y times y = 8 times 8 + 5 times 5 = 64 + 25 = 89
Square of X + square of y = 89

3b-3c + 1 simplification

It can't be simplified any more. It's the simplest

Simplify (a-2b + 3C) 3
It's too simple to be further simplified
The last three is cubic

（a-2b+3c)³=(a-2b)³+3(a-2b)²*3c+3(a-2b)(3c)²+(3c)³=a³-6a²b+12ab²-8b³+9a²c-36abc+36b²c+27ac²-54bc²+27c³

How to simplify (- 3) * 2Ab + 5ab * 6

The original formula = - 6ab + 30ab = 24ab

1. Fraction: compare the size of 1 / A + 1 and a + 1 / A + 2. Fraction: 1 / A + 1 / b = 1 / A + B, it is urgent to find the value of fraction B / A + A / b

1. Fraction:
1/a+1＜a+1/a+2；
2. Fraction:
Multiply both sides by (a + b)
1+b/a+1+a/b=1
So: B / A + A / b = - 1

Let the value of fraction-7 / (1-4x) be positive if
Just answer the range of x =

-7/(1-4x)>0
1-4x1/4

Ask a math problem, when x > 2, try to compare the value of fraction (X-2) / (x-1) and (x-3) / (X-2)

(x-2)/(x-1)
=(x-1-1)/(x-1)
=(x-1)/(x-1)-1/(x-1)
=1-1/(x-1)
(x-3)/(x-2)
=(x-2-1)/(x-2)
=(x-2)/(x-2)-1/(x-2)
=1-1/(x-2)
x>2
So X-1 > X-2 > 0
So 1 / (x-1) - 1 / (X-2)
-1/(x-1)>1-1/(x-2)
So (X-2) / (x-1) > (x-3) / (X-2)