3x + 5 (138-x) = 540

3x + 5 (138-x) = 540

seventy-five

How to calculate (3 / 8) + (4 / 9)) * 8 * 9 simply
It must be easy to calculate!

[(3/8)+(4/9)]*8*9
=[(3/8)*8*9]+[(4/9)*9*8]
=(3*9)+(4*8)
=27+32
=59

As shown in the figure, in the semicircle o with radius r, radius OA ⊥ diameter BC, point E and point F slide on AB and AC respectively, and AE = CF is maintained, but point F does not coincide with AC, and point E does not coincide with BA
(1) Proof: s quadrilateral aeof = half r square
(2) Let AE = x, s △ OEF = y, write the functional relationship between Y and X, and find the value range of X
eldest brother! This is the homework due tomorrow

It can be proved that triangle OEA is equal to triangle OCF
So s quadrilateral aeof = s triangle OCF + s triangle ofa
So s quadrilateral aeof = half r squared
I'll think about the second question tomorrow

How much is the current price of a drug after 35% price reduction and 20% price reduction?

(1-35%)(1-20%)=52%

It is known that the function f (x) whose domain of definition is (0, + ∞) satisfies that for any x ∈ (0, + ∞), f (2x) = 2F (x) holds; when x ∈ (1,2], f (x) = 2-x, if X1 and X2 are two real roots of the equation f (x) = a (0 < a ≤ 1), then x1-x2 cannot be a function
A24 B72 C96 D120

When x ∈ (2,4], f (x) = 2F [2 - (X-2)] = 2F (4-x) (also a straight line, the same as when x ∈ (1,2], a bit similar to periodic function), f (3) = 1, f (4) = 0, the same method can make x ∈ (4,8] and so on, function 0 point is x = 1,2,4,8 , 2 ^ n-1; because 0

How to determine I and s in the program diagram of senior high school mathematics compulsory three?

In the program diagram, I is usually a loop variable, and the loop process is terminated by judging it. The initial value of I is usually determined according to the topic meaning, and in many cases, the initial value is 0 or 1
S usually represents sum, and the initial value is usually 0. The expression about s is usually listed according to the meaning of the topic, which is to assign a value to s

The price of a color TV set is 2430 yuan after two consecutive price cuts of 10%. How much is the original price of this color TV set?
How much is the original price of a color TV set? After a continuous reduction of 10%, the price is 2430

3000

What are leap years in 1990, 1998, 2000, 2008, 2010 and 2020?

You can divide it by 4 ~ 2000, 2008, 2020

1. Simplify the following numbers
+(+5)=______ +（—9）=_______
2. Xiao Li drew a number axis when he was working on the problem. There was a point a on the number axis, which represented the number - 3. Due to carelessness, he marked the origin of the number axis wrong, so that the point a just fell on the position of the opposite number of - 3. To draw the number axis correctly, which direction should the origin move several units of length_________________ .
3. Calculation problem
1/1x3+1/3x5+.+1/99x101

The two elder brothers upstairs each made a mistake
5 -9
Move 6 units to the right
50/101

3,1 in football,

It is the scoring principle of football game: win a game and get 3 points (2 points at the earliest time); draw a game and get 1 point; lose a game and get no point (0 point)