There is a batch of cement on the construction site. 40% of the cement is transported in the first time and 35% in the second time. There are 17 tons left. How many tons are there?

17 divided by 1 - 40% - 35%, the quotient is 68 tons

If the quadratic equation (x-a) ^ 2 + n = 0 with respect to X has a real number solution, find the value range of the real number n

(x-a)^2+n=0
(x-a)^2=-n
(x-a)^2≥0
So - n ≥ 0
n≤0

There are two piles of sand, a and B, with a weight ratio of 4:7. If both piles of sand are transported to 1.5 tons, then the ratio of the two piles of sand is 3:5. How many tons of sand are there in pile a?

Suppose a's original mass is 4x tons
4X+1.5：7X+1.5=3：5
3(7X+1.5)=5(4X+1.5)
21X+4.5=20X+7.5
X=3
A = 3 * 4 = 12 tons

If two of LG ^ x-lgx ^ - 2 = 0 are a and B, then the value of LGB ／ LGA + LGA ／ LGB is
^It means 2

lgB/lgA+lgA/lgB = ((lgB)^2+(lgA)^2)/(lgA*lgB)=((lgA+lgB)^2-2*lgA*lgB)/(lgA*lgB)
=((lgA+lgB)^2/(lgA*lgB)-2
According to Weida's theorem, we can get LGA + LGB = 2, LGA * LGB = - 2
Substituting the above formula, we get - 4

The number of male workers in a factory is 25% of the total number of employees in the factory. Later, 100 male and 100 female workers were recruited. At this time, the number of male workers accounts for 512% of the total number of employees in the factory. How many employees are there now?

Suppose there are x employees in the whole plant, from the meaning of the question, we can get: 25X + 100 = (x + 100 + 100) × 512, & nbsp; & nbsp; & nbsp; & nbsp; & nbsp; & nbsp; & nbsp; & nbsp; & nbsp; & nbsp; & nbsp; & nbsp; & nbsp; & nbsp; 25X + 100 = 512x + 200 × 512, & nbsp; & nbsp; & nbsp; & nbsp; & nbsp; & nbsp; & nbsp

Given that x plus y equals 110 and XY equals 33, find the value of (2x minus 3Y minus 2XY) minus (x minus 4Y plus XY)

（2X-3Y-2XY)-(X-4Y+XY)
=2X-3Y-2XY-X+4Y-XY
=X+Y-3XY
Because x plus y equals 110, XY equals 33
So the original formula is 110-33 * 3 = 11

In 2012 London Olympic Games, China won 30 gold medals, and Russia won 12 out of 19 gold medals. How many gold medals did Russia win
Answer quickly

30 × 12 / 19 = 360 / 19 (pieces)
(Note: I suspect the data in your question is wrong)

Known: x 2 + XY + y = 14, y 2 + XY + x = 28, find the value of X + y

∵ x2 + XY + y = 14 (1), Y2 + XY + x = 28 (2), ∵ ① + 2, we get: x2 + 2XY + Y2 + X + y = 42, ∵ (x + y) 2 + (x + y) - 42 = 0, ∵ (x + y + 7) (x + y-6) = 0, ∵ x + y + 7 = 0 or x + y-6 = 0, the solution is: x + y = - 7 or x + y = 6

A class of a students participate in tree planting activities, including B boys (b < a), if only completed by boys, each need to plant 15 trees; if only completed by girls, each need to plant trees______ A tree

The total number of trees planted is 15b, and the number of girls is A-B, so each girl needs to plant 15ba − B trees

Square root 23 is between integer () and integer ()

Square root 23 is between integer (4) and integer (5)

There is a batch of cement on the construction site. 40% of the cement is transported in the first time and 35% in the second time. There are 17 tons left. How many tons are there?