She was so interested in the book that she read it all night

She was so interested in the book that she read it overnight.

The English translation of "books should be read selectively, and books with teaching and entertainment are more beneficial"

Reading shouid be selective, and the books that contained knowledge in fun making is more beneficial

If the solutions of equation 13X = 1 and 2x + a = ax are the same, then a=______ ．

13X = 1 & nbsp; 13X ／ 13 = 1 ／ 13 & nbsp; & nbsp; & nbsp; & nbsp; & nbsp; X = 3; substitute x = 3 into 2x + a = ax, get: 2 × 3 + a = 3A & nbsp; 6 + A-A = 3a-a & nbsp; & nbsp; & nbsp; & nbsp; & nbsp; & nbsp; & nbsp; & nbsp; & nbsp; & nbsp; & nbsp; & nbsp; & nbsp; & nbsp; & nbsp; a = 3; so the answer is

9.73 - (3.2-0.27)

9.73-(3.2-0.27)=（9.73+0.27）-3.2=6.8

If 9 ^ n · 27 ^ n-1 / 3 ^ 3N + 1 = 81, find the value of n ^ - 2. If the answer is good, bonus will be added

9^n×27^(n-1)÷3^(3n+1)=81(3²)^n×(3³)^(n-1)÷3^(3n+1)=3^4(3^2n)×[3^3(n-1)]÷3^(3n+1)=3^4(3^2n)×[3^(3n-3)]÷[3^(3n+1)]=3^43^[2n+(3n-3)-(3n+1)]=3^43^(2n+3n-3-3n-1)=3^43^(2n-4)=3^42n-4=4n=4n...

A polynomial a subtracts the quadratic power of the polynomial 3x + 6x-7. Xiao Ming copied the minus sign into the plus sign, and the result is the quadratic power of - 2x - 9. Get the correct result

A= -2x²-9-（3x²+6x-7）
= -2x²-9-3x²-6x+7
= -5x²-6x-2
Correct results: - 5x & # 178; - 6x-2 - (3x & # 178; + 6x-7)
= -5x²-6x-2-3x²-6x+7
= -8x²-12x+5

21 minus two times three
Do you want to change the sign first or take the train first?

This is the operation rule, but for the multiplication and division method, you can put forward the negative sign first. In the multiplication and division with negative sign, the result of odd negative number is negative, and that of even negative number is positive, except for some special columns, such as a number is square

How to solve the nonhomogeneous first order differential equation f '(T) + F (T) + 2 = 0?

Let y = f (T)
Then y '+ y + 2 = 0
dy/dx=-(y+2)
1/(y+2) dy=-1 dx
Take the integral from both sides to get:
ln(y+2)=-x
y+2=e^(-x)
y=e^(-x)-2
Namely
f(t)=e^(-t)-2
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The equation x ^ 2-ax + A ^ 2-4 = 0 of X has two positive roots

Let f (x) = x ^ 2-ax + A ^ 2-4, because when f (x) = 0, he has two positive roots, then his image is on the right side of the Y axis (you can draw a rough image of him, that is, a U-shape). Then only three conditions need to be satisfied to fix the image. 1. If there are two roots, then B ^ 2-4ac & gt; 0, that is a ^ 2-4 (a ^ 2-4) & gt; 0, you can get - 4 / radical 3 & lt; a & lt; 4 / radical 32. F (0) & gt; 0, that is 0-0 + A ^ 2-4 & gt; 0, We can get a & gt; 2 or a & lt; - 23. The symmetry axis is on the right side of the Y axis, that is - B / 2A & gt; 0. In this case, it is a / 2 & gt; 0, that is a & gt; 0. In conclusion, 2 & lt; X & lt; 4 / radical 3

She was so interested in the book that she read it all night