3x2 + 4x-2x2-x + x2-3x-1, where x = 3 Combine the following polynomials and substitute them for evaluation

3x2 + 4x-2x2-x + x2-3x-1, where x = 3 Combine the following polynomials and substitute them for evaluation

3x2 + 4x-2x2-x + - 3x-1 = 6x2-1, where x = 3, 6x2-1 = 6 * 32-1 = 6 * 9-1 = 54-1 = 53

If the product of the polynomials ax & # 178; + BX + 1 and 2x & # 178; - 3x + 1 does not contain the cubic term and the first term of X, find the values of a and B

First, we analyze which items can appear three times, a multiplied by - 3, 2 multiplied by B, so - 3A plus 2B equals 0, the first term is B multiplied by 1, - 3 multiplied by 1, so - 3 plus B equals 0, B is 3
I hope I can help you

Given the polynomial x 3-2x + AX-1 divided by B X-1, the quotient is x 2-x + 2, the remainder is 1, find the value of a and B

From the meaning of the title, we can see that x3-2x + AX-1 = (BX-1) × (x2-x + 2) + 1, which is sorted out as follows: x3-2x2 + AX-1 = BX3 + (- B-1) x2 + (2B + 1) X-1, х B = 1, a = 2B + 1, х a = 3, B = 1

Why can the summation formula be simplified in the case of equal ratio sequence A1 = q
The common ratio equals the first term, not 1
It's just like finding the sum of 7 plus 7 once plus 7 twice plus 7 9 times
His formula can be simplified. Why not use the original formula

There is nothing simpler to simplify
Sn=q(1-q^n)/(1-q)=q[q^(n-1)+q^(n-2)+… +q+1]=q^n+q^(n-1)+… q^2+q
No more comfortable than the original formula!
Are you looking for a simple way to calculate?
You can only turn to logarithm table or excel function (you can enter the following in a cell: = x ^ (y), and then enter (x is the base, y is the index))

The summation formula of equal ratio sequence is [A1 (1-Q ^ n)] / (1-Q). How can the limit A1 / (1-Q) of this formula be derived?

Only | Q|

Y ^ 4-8y ^ 2 + 16 factorization

y^4-8y^2+16
=(y^2-4)²
=(y-2)²(y+2)²

The perimeter of a rectangle is 30cm. If the length of one side of the rectangle is expressed by the letter X (unit: cm), the area of the rectangle can be expressed as______ cm2．

∵ the perimeter of a rectangle is 30cm, one side of the rectangle is x, the other side of the rectangle is 12 (30-2x) = 15-x, and the area of the rectangle is x (15-x) (cm2), so the answer is x (15-x)

Let the area of a rectangle be s and the length be a. the circumference of the rectangle is expressed by the algebraic expression of S and a

S = length * width, length = a, ｜ width = s / A
Perimeter = 2 (length + width) = 2 (a + S / a)

A parallelogram is cut along the height to form a rectangle. The area of the rectangle is 140 square meters. What is the perimeter of the rectangle?

A lot, but the bottom elevation of a parallelogram multiplied by 2 is the perimeter of a rectangle

The circumference of a rectangle is 72 cm, and the ratio of length to width is 4:5. What is the area of a rectangle?

5 + 4 = 9 (parts) length: 72 ／ 2 × 59 = 36 × 59 = 20 (CM) width: 72 ／ 2 × 49 = 36 × 49 = 16 (CM) area: 20 × 16 = 320 (square cm) answer: the area of this rectangle is 320 square cm