The decomposition factors are: (1) (x + y) 2-4a2; (2) 49 (a + b) 2-16 (a-b) 2; (3) 8x2ny2-2z2m + 4

The decomposition factors are: (1) (x + y) 2-4a2; (2) 49 (a + b) 2-16 (a-b) 2; (3) 8x2ny2-2z2m + 4

（1）（x+y）2-4a2=（x+y+2a）（x+y-2a）；（2）49（a+b）2-16（a-b）2=[7（a+b）+4（a-b）][7（a+b）-4（a-b）]=（7a+7b+4a-4b）（7a+7b-4a+4b）=（11a+3b）（3a+11b）；（3）8x2ny2-2z2m+4=2（4x2ny2-z2m+4）=2（2...

9（a-b）2-16（a+b）2．

9（a-b）2-16（a+b）2=[3（a-b）]2-[4（a+b）]2=[3（a-b）-4（a+b）][3（a-b）+4（a+b）]=[3a-3b-4a-4b][3a-3b+4a+4b]=-（a+7b）（7a+b）．

Factorization of 16 (a-b) ^ 2-24 (a ^ 2-B ^ 2) + 9 (a + b) ^ 2

16(a-b)^2-24(a^2-b^2)+9(a+b)^2
=[4(a-b)]^2-2*4*3(a-b)(a+b)+[3(a+b)]^2
=[4(a-b)-3(a+b)]^2
=(a-7b)^2

When the height of a cuboid is increased by 5 meters, it becomes a cube, and its surface area is increased by 160 square meters. The original cuboid volume is () cubic meters, with the largest area
When the height of a cuboid is increased by 5 meters, it becomes a cube, and its surface area is increased by 160 square meters. How many cubic meters is the volume of the original cuboid, which two sides surround the largest area, and how many are the smallest?

Let the length and width of the cuboid be X
The 160 square meters increase in surface area comes from the increase in the area of four sides, i.e
x*5*4=160 x=8
So the length, width and height of the original cuboid were 8m, 8m and 3M respectively
Volume v = 8 * 8 * 3 = 192 M3
The largest areas are the upper and lower surfaces
The smallest is four sides

3.3.6.8 how to calculate 24 o'clock

3×3＝99-6＝33×8＝24

The curve symmetric to sine function y = SiNx (x belongs to R) about x = 270 degrees is y = SiNx? Y = - SiNx?
The former is correct
I don't understand
Y = - SiNx? Why not?
Isn't SiNx - SiNx symmetric

When x = 270 degrees, SiNx gets the minimum value of - 1. According to the image, it is symmetrical with y = SiNx, and the same is true when x = 90 degrees. When x = 180 or 0, the symmetrical image is y = - SiNx. Your puzzle is that the symmetry problem is not clear, about point symmetry or about line symmetry, about x = ah or y = a symmetry is even function, about point pair

When a wax block (density 900 kg / m ^ 3) is still in alcohol (density 800 kg / m ^ 3), its buoyancy is
When a wax block (with a density of 900 kg / m ^ 3) is still in alcohol (with a density of 800 kg / m ^ 3), the buoyancy it receives is 1.6 n. if it is put into water, how much buoyancy it receives when it is still?

V wax = f alcohol floating / (ρ liquor * g)
M wax = ρ wax V wax
F water floatation = m / g
LIANLI, get
F water floatation = (ρ wax / ρ wine) f alcohol floatation = 1.8n
Don't talk nonsense on the first floor. You'll forget everything from high school when you go to college

If we know that the vertex of a regular hexagon is on the same sphere, and the volume of the hexagon is 9 / 8, and the perimeter of the bottom is 3, then the volume of the sphere is?

The perimeter of the base of the hexagonal prism is 3,
So the length of the bottom side is 1 / 2,
So the bottom area is 3 √ 3 / 8,
So the height is √ 3
So the radius of the ball is 1 (the length from the center of the bottom to the center of the ball is half of the height, that is √ 3 / 2, and the length from the center of the bottom to a vertex is 1 / 2. According to the Pythagorean theorem, the length from the center of the ball to a vertex (the vertex is on the spherical surface) is 1, that is the radius of the ball)
The volume is 4 * π / 3

In the plane rectangular coordinate system xoy, point P is on the curve C: y = x3-10x + 3, and in the second quadrant, if the tangent slope of curve C at point P is known to be 2, then the coordinate of point P is______ ．

Let P (x0, Y0) (x0 ＜ 0). From the meaning of the question, we know that y ′| x = x0 = 3x02-10 = 2, X02 = 4. X0 = - 2, Y0 = 15

Road construction site transported 2000 cubic meters of concrete. The width of the paved road is 8 meters and the thickness is 25 cm. How many meters of road can these concrete pave?

25cm = 0.25m
2000÷(8×0.25)
=2000÷2
=1000 meters
A: the concrete can pave a road 1000 meters long