A 20 cm long, 15 cm wide and 12 cm deep rectangular water tank has a water depth of 6 cm. After a cube stone is put in, the water depth is 10 cm. What is the volume of the stone?

A 20 cm long, 15 cm wide and 12 cm deep rectangular water tank has a water depth of 6 cm. After a cube stone is put in, the water depth is 10 cm. What is the volume of the stone?

20 × 15 × (10-6) = 20 × 15 × 4 = 300 × 4 = 1200 (CC). A: the volume of this stone is 1200 CC

A 20 cm long, 15 cm wide and 12 cm deep rectangular water tank has a water depth of 6 cm. After a cube stone is put in, the water depth is 10 cm. What is the volume of the stone?

20 × 15 × (10-6) = 20 × 15 × 4 = 300 × 4 = 1200 (CC). A: the volume of this stone is 1200 CC

Is the parallelogram rule and triangle rule in physics the same?

The essence is the same

A school organizes students to take part in summer camp. It rents the same kind of van. If each bus takes 28 people, 13 people can't get on the bus. If each bus takes 32 people, there are still three vacant seats. How many students and how many cars are there?

Suppose x people and Y cars x-28y = 13 x-32y = - 3 x = 125 y = 4

If a natural number can be expressed as the square difference of two natural numbers, then the natural number is a wisdom number. Starting from 1 in the natural number sequence, the 1990 th wisdom number is many

We should first find the distribution law of wisdom number. Because 2K + 1 = (K + 1) 2 - K2, obviously, every number greater than 4 and multiple of 4 is also wisdom number. Therefore, even numbers divided by 4 and remaining 2 are not wisdom numbers. Therefore, the smallest wisdom number in natural number sequence is 3, and the second wisdom number is 5, starting from 5, followed by 5, 7, 8; 9, 1

The general term formula of sequence {an} is an = 5 × (25) 2n − 2 − 4 × (25) n − 1, the maximum term of sequence {an} is the X term, and the minimum term is the Y term, then x + y is equal to ()
A. 3B. 4C. 5D. 6

∵ an = 5 × (25) 2n − 2 − 4 × (25) n − 1, let (25) n-1 = t, then t is the decreasing function of N, t ∈ (0, 1], an = 5T2 − 4T, the symmetry axis is a quadratic function of T = 25, when t = 1, that is, when n = 1, an gets the maximum value, when t = 25, that is, when n = 1, an gets the minimum value, ∵ x = 1, y = 2, x + y = 3, so a is selected

The number of people on a bus is four times that on a minibus. When two buses arrive at a station, there are 38 people on the bus and 2 people on the minibus. At this time, the number of people left on the two buses is equal. How many people are there on the bus?

The number of people on a bus is four times that on a minibus. When two buses arrive at a station, there are 38 people on the bus and 2 people on the minibus. At this time, the number of people left on the two buses is equal. How many people are there on the bus?
(38-2)÷（4-1）×4
=36÷3×4
=12×4
=48

lim→1(x³-2x+1)/(x²-1)

(x^3-2x+1)/(x^2-1)
=[x(x^2-1)-(x-1)]/(x^2-1)
=x-(1/(x+1)
lim->1 = 1-1/2=1/2

If two of the equations LG ^ 2x + (LG2 + Lg3) * lgx + LG2 * Lg3 = 0 are X1 and X2, then the value of X1 * X2 is?
It's like the exchange method? I really can't think of it

In addition, the original formula of lgx = t is T ^ 2 + (LG2 + Lg3) t + LG2 * Lg3 = 0. By cross multiplication, (T + LG2) * (T + Lg3) = 0, T1 = - LG2 or T2 = - Lg3, that is, lgx = - LG2 or lgx = - Lg3, so X1 = 1 / 2, X2 = 1 / 3, so x1x2 = 1 / 6

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