X plus four fifths equals 450

X plus four fifths equals 450

X + 4x / 5 = 450, that is, x + 4x / 5 = 9x / 5 = 450
X + 4x / 5 = 450
9 / 5 x = 450
=450 divided by 9 / 5
=2250 out of 9
=250 out of 1
=3
You are wrong. The correct answer is 3
If x2 + 7xy + ky2-5x + 43y-24 can be decomposed into the product of two first-order factors, the value of K can be obtained
It should be the method of undetermined coefficient. It's very troublesome for me to calculate,
Another way is to use double cross multiplication
See Encyclopedia for specific definitions
Let K be decomposed into K1 and K2
-24 is decomposed into M1 and M2
There are
1 k1 m1
1 k2 m2
That is, 1 * M1 + 1 * M2 = 5
So M1 = 3 M2 = - 8
Then K1 + K2 = 7
-8*k1+3*k2=43
The solution is K1 = - 2, K2 = 9
So k = - 18
Let x ^ 2 + 7xy + KY ^ 2-5x + 43y-24 = (x + ay + b) (x + CY + D)
It unfolds well
x^2+acy^2+(a+c)xy+(b+d)x+(ad+bc)y+bd=
x^2+7xy+ky^2-5x+43y-24
therefore
ac=k
a+c=7
b+d=-5
ad+bc=43
bd=-24
Solution
A = - 2 b = 3 C... expansion
Let x ^ 2 + 7xy + KY ^ 2-5x + 43y-24 = (x + ay + b) (x + CY + D)
It unfolds well
x^2+acy^2+(a+c)xy+(b+d)x+(ad+bc)y+bd=
x^2+7xy+ky^2-5x+43y-24
therefore
ac=k
a+c=7
b+d=-5
ad+bc=43
bd=-24
Solution
a=-2 b=3 c=9 d=-8 k=-18
That is, X * x + 7xy-18y * y-5x + 43y-24 = (x + 9y-8) (x-2y + 3) question: I also use this method, but I think it's too troublesome
Finding the general term formula of sequence
1 3 6 10.
1 4 9 16. How to find the general term formula as an example
Please write the process clear and easy to understand, not too cumbersome
Finding the general term basically belongs to the method of observation. There is no specific way, because your data is specific. For example, the second of the two is square. The first is like + 2, + 3, + 4
Question 1: 1 = 1 3 = 1 + 2 6 = 1 + 2 + 3 10 = 1 + 2 + 3 + 4, so there is a formula (you should know. The formula of continuous addition) so it is (n * n + 1) / 2
Question 2: N2 (square)
Basically, there are no specific numbers in the general term, and then it can be solved according to different ways, and the specific data is observation
Find the tolerance K, where k = n, the general formula is n (n + 1) / 2
In the second, k = 2N-1, the general formula of accumulation is n ^ 2
Finding the general term basically belongs to the observation method... There is no specific way, because your data is specific, like the second of the two, you can see that it is a square relationship, the first is like + 2, + 3, + 4... Then we can know their general expressions are as follows:
Question 1: 1 = 1 3 = 1 + 2 6 = 1 + 2 + 3 10 = 1 + 2 + 3 + 4, so there is a formula (you should know.).. The formula of continuous addition is (n * n + 1) / 2
Question 2: it's n ^ 2... Expansion
Finding the general term basically belongs to the observation method... There is no specific way, because your data is specific, like the second of the two, you can see that it is a square relationship, the first is like + 2, + 3, + 4... Then we can know their general expressions are as follows:
Question 1: 1 = 1 3 = 1 + 2 6 = 1 + 2 + 3 10 = 1 + 2 + 3 + 4, so there is a formula (you should know.).. The formula of continuous addition is (n * n + 1) / 2
Question 2: put n ^ 2 away
There is a problem: calculate the value of (2x ^ 4-4x ^ 3y-2x ^ 2Y ^ 2) - (x ^ 4-2x ^ 2Y ^ 2 + y ^ 3) + (- x ^ 4 + 4x ^ 3y-y ^ 3), where x = 2010, y = - 1
Mistakenly copy "x = 2010" to "x = 2001", but his calculation result is also correct. Why do you say that?
(2x^4-4x^3y-2x^2y^2)-(x^4-2x^2y^2+y^3)+(-x^4+4x^3y-y^3)=2x^4-4x^3y-2x^2y^2-x^4+2x^2y^2-y^3-x^4+4x^3y-y^3=2x^4-x^4-x^4+4x^3y-4x^3y-2x^2y^2+2x^2y^2-y^3-y^3=4x^3y-4x^3y-2x^2y^2+2x^2y^2-y^3-y^3=-2x^2y^2+2...
Original formula = 2x ^ 4-4x ^ 3y-2x ^ 2Y ^ 2-x ^ 4-2x ^ 2Y ^ 2-y ^ 3-x ^ 4 + 4x ^ 3y-y ^ 3 = 2 × y ^ 3
So the result has nothing to do with X
Factorization of x5-x4 + X3 + x2 + X + 1
Ls you didn't write it right
(X+1)(X^4-X^3+X^2+1)
=1 + X + X^2 + X^5
If the title is:
x^5 - x^4 + x^3 + x^2 + 1
There is no factor to lift
X5-X4+X3+X2+X+1
=X^3(X^2-1)+X^2(X+1)+(X+1)
=X^3(X+1)(X-1)+X^2(X+1)+(X+1)
=(X+1)(X^4-X^3+X^2+1)
What's it from? What is X5? Is it 5x?
What is the formula for finding the general term of a sequence by difference method
Take another example
Let {an} be the difference sequence of order r and DK be the first term of order k (1)
There is a problem: calculate the value of (2x ^ 4-4x ^ 3-2x ^ 2Y ^ 2) - (x ^ 4-2x ^ 2Y ^ 2 + Y3) + (- x ^ 4 + 4x ^ 3y-y ^ 3), where x = 1 / 4, y = - 1
Student a mistakenly copied x = 1 / 4 to x = - 1 / 4, but his calculation result is also correct. Why do you say that?
(2x ^ 4-4x ^ 3y-2x ^ 2Y ^ 2) - (x ^ 4-2x ^ 2Y ^ 2 + Y3) + (- x ^ 4 + 4x ^ 3y-y ^ 3) = 2x ^ 4-4x ^ 3y-2x ^ 2Y ^ 2-x ^ 4 + 2x ^ 2Y ^ 2-y ^ 3-x ^ 4 + 4x ^ 3y-y ^ 3 = (2x ^ 4-x ^ 4) - (4x ^ 3y-4x ^ 3Y) + (- 2x ^ 2Y ^ 2 + 2x ^ 2Y ^ 2) + (- y ^ 3-y ^ 3) = (4y-4y) x ^ 3-2y ^ 3 = - 2Y ^ 3 this result has no relation with x value
Factorization x5n + xn + 1 2a2-a2b + (b-2) (AB-A) 2 X5 + X4 + X3 + x2 + X + 1 X4 + y4-2x2y2-2x2-2y2 + 1
Solving general term formula by sequence λ method
For example, if A0 is known to be a constant and N ∈ n, an = 3 Λ (n-1) - 2A (n-1)
Ask {an}?
an+3^n=-2[a(n-1)+3^(n-1)]
{an + 3 ^ n} is an equal ratio sequence
an+3^n=(a0+1)*(-2)^(n-1)
an=(a0+1)*(-2)^(n-1)-3^n
x²+4x-9=2x-11 x²-X-4/7=0 X²-x-4/3=0 4x²-x-9=0
x²+4x-9=2x-11
x²+2x+2=0
x²+2x+1+1=0
(x+1)^2=-1
The equation has no real solution
x²-X-4/7=0
x²-X+(1/2)^2-(1/2)^2-4/7=0
(x - 1/2)^2=23/28
x=1/2 ±√23/28
x=(7 ±√161)/14
X²-x-4/3=0
X²-x+(1/2)^2-(1/2)^2-4/3=0
(x-1/2)^2=19/12
x=(3 ±√57)/6
4x²-x-9=0
The solution is obtained by formula method
x=(1±√1+4*4*9)/2*4
x=(1±√145)/8