First divide, then compare the size 1.5/9 and 7 / 10 2.7/8 and 9 / 10

First divide, then compare the size 1.5/9 and 7 / 10 2.7/8 and 9 / 10

Question 1: 50 / 90 after 5 / 9, 63 / 90 after 7 / 10, 63 > 50, so 5 / 9 is less than 7 / 10
Question 2: 70 / 80 after 7 / 8, 72 / 80 after 9 / 10, 72 > 70, so 7 / 8 is less than 9 / 10
Do you understand?

How to divide 2 and 1 / 3?

First, change 2 and 1 / 3 into a false score of 7 / 3, and then go to the general score

-Square 4a, square B + 4ab-1
-The cubic factorization factor of the third power X + 12ax of 3A

-Square 4a, square B + 4ab-1
=-（4a²b²-4ab+1）
=-(2ab-1)²
-The third power of 3A + the third power of 12ax
=3ax(4x²-a²)
=3ax(2x+a)(2x-a)
If you don't understand this question, you can ask,

The area of the first plot is 100 square meters more than three times that of the second plot. The total area of the two plots is 2900 square meters. How much is it

If the second plot is x square meters, the first plot is 3x + 100 square meters,
According to the equation: x + (3x + 100) = 2900
4x =2900-100
4x =2800
x =700
The first block: 3x + 100 = 3 * 700 + 100 = 2200
A: the first plot is 2200 square meters, and the second plot is 700 square meters

If the midpoint m of the string PQ in the circle O passes through the point m, then M is the midpoint of XY if the two strings AB, CD, ad and BC intersect PQ at x and Y respectively?

This is the Butterfly Theorem in a circle, which can be proved with the help of the angle theorem

Factorization for solving equations
1296x^4-1800x^3+513x^2-200x+41=0

1296(x^4) - 1800x"' + 513x" - 200x + 41 = 0
Factorization
( 144x" )( 9x" ) - ( 200x )( 9x" ) + ( 144 + 369 )x" - 200x + 41 = 0
( 144x" )( 9x" ) + 144x" - ( 200x )( 9x" ) - 200x + 369x" + 41 = 0
( 144x" )( 9x" + 1 ) - 200x( 9x" + 1 ) + 41( 9x" + 1 ) = 0
( 9x" + 1 )( 144x" - 200x + 41 ) = 0
perhaps
( 144x" )( 9x" ) - ( 200x )( 9x" ) + 41( 9x" ) + 144x" - 200x + 41 = 0
( 9x" )( 144x" - 200x + 41 ) + ( 144x" - 200x + 41 ) = 0
( 9x" + 1 )( 144x" - 200x + 41 ) = 0
Continue to decompose
[ 9x" - (-1) ]( 144x" - 36x - 164x + 41 ) = 0
( 3x + i )( 3x - i )[ 36x( 4x - 1 ) - 41( 4x - 1 ) ] = 0
( 3x + i )( 3x - i )( 4x - 1 )( 36x - 41 ) = 0
To solve the equation, two real solutions, that is
x1 = 1/4 ,
x2 = 41/36 ,
There are also two complex solutions
x3 = (1/3)i
x4 = -(1/3)i

If the tangent of circle (x-1) 2 + (y + 3) 2 = 1 is made through point P (2,4), then the tangent equation is______ ．

When the tangent slope does not exist, the tangent equation is x = 2. When the tangent slope exists, let the tangent equation be y-4 = K (X-2), that is, kx-y + 4-2k = 0, and then according to the distance from the center (1, - 3) to the tangent equal to the radius, we can get | K + 3 + 4 − 2K | K2 + 1 = 1, and get k = 247, so the tangent equation is 24x-7y-20 = 0

Given x, y ∈ R, compare the size x ^ 2 + y ^ 2 with XY
Compare Size X ^ 2 + y ^ 2______ xy
How can we make a difference?

x²-xy+y²
=x²-xy+y²/4+3y²/4
=(x+y/2)²+3y²/4≥0
So x & # 178; + Y & # 178; ≥ XY

As shown in the figure, in the quadrilateral p-abcd, PD is perpendicular to the plane ABCD, PD = DC = BC = 1, ab = 2, AB is parallel to DC, and the angle BCD = 90 degrees, (1) find PC perpendicular B, (2) find the distance from point a to plane PBC; I can't get the figure,
Urgent! Half term examination!

The first question is wrong
Did you set anything up?
Why can't I answer all the questions

For any a, cos ^ 2a-2msin a-2m-2 is always less than 0, the range of real number m is obtained

The protoplast transformed into 1-x ^ 2-2mx-2m-2