Please help the math masters, please help you solve it

Solution: If there are x red balls, then there are (x+50) white balls.

x-50)*3=x+50

3x-150=x+50

2x=200

x=100, i.e. x+50=150

Answer: There are 150 white balls. Pick B

Let there be x red balls, then there are x+50 white balls, each time take away 1 red ball and 3 white balls, and the surplus of red balls is 50, indicating that x-50 red balls are taken away, and 3*(x-50) white balls, then the equation can be listed as the total number of balls x+x+50=(x-50)+3(x-50)+50, and the solution is x=100, so the total number of balls is x+x+50=250.

Select D.

Set the red ball x and the white ball y

then y=x+50

The number of times you take three white balls each time (x+50) 3, at this time, you will get a total of x-50 red balls.

x+50)/3=x-50

x+50=3x-150

2x=200

x = 100 white ball y = 100 + 50 = 150

Total 100 + 150 = 250 balls.

D solution: If there are x red balls, then the white balls x + 50.

3（x-50)=x+50

Get x=100

Finally, this pair of red and white balls has a total of x+x+50=250

Solution: Shift the term to obtain: (1-2x/3-4x)-1 0 pass to obtain: (x-1) (2x-1) 0

So there is: x-1 0

2x-1>0

Solution: 1 2 x 1

Or: x-1 0

2x-1<0

There is no solution to this group of inequalities.

In summary, the solution set is 1 2 x 1

1。When m=1 2, the derivative of f(x) is obtained:

f (x)=3x -x-2=(3x+2)(x-1) so that f (x)=(3x+2)(x-1)>0 solves: x>1 or x<-2 3 where f(x) increases monotonically.

Let f (x)=(3x+2)(x-1)<0 solve:-2 37 In summary:k is in the range of (7,+

1) First look at the two boys as a combination, then the sedan beam loses this combination and 5 girls, a66 (a superscript and a closed subscript, the same below is 6x5x4x3x2x1), and then the two boys' positions can be interchanged, x2, so the answer is 1440 kinds.

2) Use the total arrangement method to subtract the first question, 3600 kinds.

Take the defective product first, there are 2 ways to take it, and then go to 4 pieces from the remaining 98 pieces, 2xcFirst take any 3 numbers from 1,3,5,7,9, there are c ) = 10 kinds, and then take any 2 numbers from 2, 4, 6, 8, there are slag tung c ) = 6 kinds, and then combine these five numbers freely, so 10x6x120 = 7200 kinds.

This question should be D, not C

It is linearly related to a1 and a2, which is conceptually linear with a1 and a2.

In principle, linear correlation means that a system of secondary linear equations is assumed, expressed as a matrix [ , a1 , a2 , 0]. There are infinitely many solutions to this system of equations, i.e., there are arbitrary x1, x2, x3 r, which can make x1* +x2*a1+x3*a2=0 true, so there must be =-(x2*a1+x3*a2) x1 true, which is just reflected by option d.