How to factorize x2 + 4x-1

How to factorize x2 + 4x-1

X2+4x-1
=(X+2+√5)(X+2-√5)

Factorization of (x2 + 1) 2-4x (x2-1)

(x^2+1)^2-4x(x^2-1)
=(x^2-1)^2-4x(x^2-1)+4x^2
=[x^2-1-2x]^2

Factorization x2 + 4x-12=___ ．

X 2 + 4x-12 = (x + 6) (X-2), so the answer is: (x + 6) (X-2)

1 / 3x-16 = (100-x) / 10 to solve the equation

The original equation can be reduced to
1/3x-16=10-1/10x
Transfer of items
（1/3+1/10)x=10+16=26
Namely: 13 / 30x = 26
So: x = 60

(6) The master and apprentice work together to process a batch of parts. They process 40 parts every day. After three days, the ratio of the number of parts processed to the total number of parts is 3:5. How many parts are there in total?
Please list the formula and complete the solution
(7) children's day book sales fell on sale on children's day 20%. Xiao Yun bought a book at 7.20 yuan. How much is the original price of this book?
Please list the formula and complete the solution

6: There are x parts in total
(40×3):x=3:5
The solution is: x = 200
7: Let the original price of the book be x yuan
x(1-20%)=7.2
The solution is: x = 9

When n approaches infinity, the limit of sequence an is A. It is proved that the limit of absolute value of an is the absolute value of A~
RT

liman=a
For any EPS > 0, there exists n > 0. When n > N, | an-a | n, | an | - | a |||

2008²-2007²+2006²-2005²+2004²-2003²+…… +2²-1²
=(2008+2007)(2008-2007)+(2006+2005)(2006-2005)+…… +(2+1)(2-1)
=2008+2007+…… +1
=2017036
Why (2008 + 2007) (2008-2007) + (2006 + 2005) (2006-2005) + +(2+1)(2-1)
=2008+2007+…… +1
I know how to get (2008 + 2007) (2008-2007) + (2006 + 2005) (2006-2005) + +(2+1)(2-1)
The key is why it = 2008 + 2007 + +1

Because 2008-2007 = 12006-2005 = 1

Simple calculation of 6.42 * 1.01-6.42

6.42*1.01-6.42
=6.42x(1.01-1)
=6.42x0.01
=0.0642

Find a differential equation with the general solution of (x-c1) 2 + (y-c2) 2 = 1

It's OK to seek the derivative on both sides, because the differential equation can be reversed
The derivation on both sides is very good
2(x-C1)+2(y-C2)*y'=0

The inequality x2-2x + 1-a2 ≥ 0

The original inequality can be reduced to (x-1) 2 ≥ A2,  when a = 0, the solution set of the inequality is R; when a > 0, X-1 ≥ a, or X-1 ≤ - A, that is, X ≥ 1 + A, or X ≤ 1-A; when a < 0, X-1 ≥ - A, or X-1 ≤ a, that is, X ≥ 1-A, or X ≤ 1 + A; when a = 0, the solution set is R; when a > 0, the solution set is {x | x ≥ 1 + A, or X ≤ 1-A}; when a < 0, the solution set is {x | x ≥ 1-A, or X ≤ 1 + a}