How to change a number into a number in billions

How to change a number into a number in billions

Count from the left; advance to eight places and add a decimal point

Use the numbers 6, 4, 3 and 2 to form an equation. The result is 24,
Each number can only be used once

6×4×(3-2)=24

Using the numbers 3, 6, 4 and 2, and adding +, -, *, / or () between them, we can get the number 24. How many expressions are there?

1、（3-2）×6×4=24
2、（6-3）×2×4=24
3、6×2+3×4=24

The simplest integer ratio of 3 / 4:9 / 10 is (): (), and the ratio is ()

The simplest integer ratio of 3 / 4:9 / 10 is (5): (6), and the ratio is (5 / 6)

Solution equation: (100-x-y) - (x + y) = 2

（100-x-y）-（x+y）=2
100-x-y-x-y =2
100-2x-2y =2
-2（x+y） =98
-（x+y） =49
That is - X-Y = 49

Volume formula and surface area formula of cube

The volume formula of cube is: edge length × edge length × edge length or cube of edge length;
Letter expression: a × a × a or the cube of A
Surface area formula of cube: S = 6 × (edge length × edge length)
Letter: S = 6A & sup2;

Given that a is the third quadrant angle, cos2a = - 3 / 5, find Tan (π / 4 + 2a)

It is known that sin2a ^ 2 + cos2a ^ 2 = 1, a is the third quadrant angle, so sin2a = - 4 / 5, tan2a = 4 / 3, so tan (π / 4 + 2a) = (Tan π / 4 + tan2a) / [1-tan4 / π tan2a] = - 7

It is better to use a simple method to solve equation 8 (x + 1) ^ 2-3 (x + 1) + 2 = 0

Let y = x + 1
8y^2-3y+2=0
Discriminant 3x3-4x8x2 = - 55

Given the equation x + (2k-1) x + k = 0 about X, find the necessary and sufficient conditions for the equation to have two real roots greater than 1,
Given the equation x + (2k-1) x + k = 0 about X, find the necessary and sufficient conditions for the equation to have two real roots greater than 1
Excuse me, why is it necessary and sufficient to use the distribution of roots? Is it necessary not to prove sufficient before proving it?

x1>1,x2>1
So x1-1 > 0, x2-1 > 0
If all are greater than 0, the sum and multiplication are greater than 0
x1+x2=-(2k-1),x1x2=k²
(x1-1)+(x2-1)>0
x1+x2-2>0
-(2k-1)-2>0
k0
x1x2-(x1+x2)+1>0
k²+2k-1+1>0
k(k+2)>0
k0
The discriminant is greater than or equal to 0
(2k-1)²-4k²>=0
-4k+1>=0
k

As shown in the figure, the coordinates of vertex C of rhombic oabc are (3,4), and vertex A is on the positive half axis of X axis. If the image with inverse scale function y = KX (x > 0) passes through vertex B, then the value of K is______ ．

∵ C (3,4), ∵ OC = 32 + 42 = 5, ∵ CB = OC = 5, then the abscissa of point B is 3 + 5 = 8, so the coordinate of B is: (8.4). Substituting the coordinate of point B into y = KX, 4 = K8, the solution is k = 32. So the answer is: 32