Factorization of (x + 1) (x-1) - 8 requires a process

Factorization of (x + 1) (x-1) - 8 requires a process

solution
(x+1)(x-1)-8
=x²-1-8
=x²-9
=(x-3)(x+3)

The following equations are solved by factorization: ① 16x & sup2; - 25 = 0, ② (x-1) (x + 3) + 4 = 0

① 16x & sup2; - 25 = (4x + 5) (4x-5) = 0 x = - 5 / 4 or 5 / 4
②（x-1）（x+3）+4=x^2+2x-3+4=(x+1)^2=0 x=-1

Use factorization to solve the following equation (2a-1) with square = 0, y (y + 5) = - 4 / 25

(2a-1)²=0
2a-1 = 0 ----- divide both sides of the equation by (2a-1)
2A = 1 ------ both sides of the equation + 1
A = 0.5 -- divide both sides of the equation by 2
y²+5y+25/4=0
(y+5/2)²=0
y+5/2=0
y=-5/2

The length of a rectangle is 2cm more than its width. If its length and width are increased by 2cm respectively, its area will be increased by 24cm square. Let the original rectangle be xcm wide and square

（x+2）（x+2+2）-x（x+2）=24

3,4,10, - 6 equals - 24
No less than five

-6*3-10+4

Let the sum of the first n terms of the sequence {an} be Sn, where an is not equal to 0. A1 is a constant, and - A1, Sn, a (n + 1) form an arithmetic sequence, and find the general formula of {an}

2Sn=a(n+1)-a1
2S(n-1)=an-a1
So 2An = a (n + 1) - an
So a (n + 1) = 3an
So an = A1 * 3 ^ (n-1)

Draw the largest circle in a square. If the square area is 16 square centimeters, then the area ratio of the square to the circle is ()

If the square area is 16 square centimeters, the side length is 4 centimeters, the diameter of the circle is 4 centimeters, and the radius of the circle is 2 centimeters
Area of circle = square of radius × π = 4 π
The area ratio of square to circle = 16:4 π = 4: π

Simple calculation of 17 × 2-23 × 7

-127

Known sample data x1, X2 If the variance of XN is 1, then data 10x1 + 5, 10x2 + 5 The variance of 10xn + 5 is______ ．

∵ sample data x1, X2 The variance of XN is 1. According to any group of data, if the variance is expanded several times at the same time, it will become square growth. Data 10x1, 10x2 The variance of 10xn is: 100 × 1 = 100, ∵ according to any group of data, add and subtract a number at the same time, the variance remains unchanged, ∵ data 10x1 + 5, 10x2 + 5 The variance of 10xn + 5 is 100, so the answer is: 100

Xiao Ming wants to put the floor tiles on the living room. Now there are two kinds of floor tiles (1.30cm * 30cm, 2.50cm * 50cm). His living room covers an area of about 36 square meters. Which one would you choose?
huh

1.3*30