The product of an unknown number multiplied by 0.8 is 7 less than that of 45 multiplied by 0.6. What is the number? Use the equation to solve the problem of "list the formulas"

The product of an unknown number multiplied by 0.8 is 7 less than that of 45 multiplied by 0.6. What is the number? Use the equation to solve the problem of "list the formulas"

Let this number be X
0.8x+7=45×0.6
0.8x+7=27
0.8x=27-7
0.8x=20
x=20÷0.8
x=25

If f (x) is a differentiable function on R and for any x with XF '(x) + F (x) > 0, then f (- 2) + F (2) is greater than or equal to or less than 0?

Greater than zero
The key is that XF '(x) + F (x) is the derivative of XF (x)
That is (XF (x)) '> 0
So XF (x) increases monotonically over R
So 2F (2) > - 2F (- 2)
2（f(2)+f(-2)）>0
So greater than

What is 38 × 19 and 18 / 19?
Hurry up

684

What is cos (190 °) equal to?

-cos10º

Given that the ratio of distance between point m and two fixed points o, (0.0) a, (3.0) is 2 / 1, find the trajectory equation of point m and explain what figure it is

This paper is intended to have the following: (check (x \\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\178; + 36 = 0; x-178; - 8x + y-178; + 12 = 0; (x-4) & 17

1/?+1/18=1/?

17: A question mark is a number, and the three denominators are all prime numbers. In this way, all the words are copied. The reasoning is as follows: first, general score, (18 + a) / 18a = 1 / B, then (18 + a) = 18a / B, and then a = 18a / B-18 = 18 (A / B-1). From this equation, it seems that

Find the solution of the system of equations x 5-y 2 = - 4 x 15-y 7 = - 3

5/x-2/y=-4.[1]
15/x-7/y=-3.[2]
[1]*3:15/x-6/y=-12.[3]
[3]-[2]:
1 / y = - 9
1 / x = (- 4-18) / 5 = - 22 / 5, that is, x = - 5 / 22

Sin 68 degrees sin 67 degrees sin 23 degrees cos 68 degrees

Original formula = sin68cos (90-67) - sin23cos68
=sin68cos23-sin23cos68
=sin(68-23)
=sin45
=Root 2 / 2

25 / 7 is 3 / 7 more than 3 / 7 of another number. Find this number (using the solution of the equation)

Let this number be x, then:
25/7-3x=3/7
3x=25/7-3/7
3x=22/7
x=22/21

Xiao Hong read two fifths of a book in eight days, how much of the book should she read every day on average? The rest of her preparation was finished in six days, how much of the book should she read every day on average

Read 1 in 20 every day, 1 in 10 every day