A cuboid uncovered iron water tank is 0.8 meters long, 0.65 meters wide and 0.6 meters high. How many square meters of iron is needed to make this water tank? If each liter of water weighs 1 kg, how many kg of water can the tank hold at most? (the thickness of iron sheet is ignored)

0.8 × 0.65 + 0.8 × 0.6 × 2 + 0.65 × 0.6 × 2 = 0.52 + 0.96 + 0.78 = 2.26 (square meter); 0.8 × 0.65 × 0.6 = 0.312 (cubic meter); 0.312 cubic meter = 312 cubic decimeter = 312 liter, 312 × 1 = 312 (kilogram); a: this water tank needs at least 2.26 square meters of iron sheet, and this water tank has the most

A cuboid iron sheet water tank without cover is 5 decimeters long, 4 decimeters wide and 6 decimeters high. How many square decimeters of iron sheet is it necessary to make such a water tank? (not included in the interface)

5 × 4 + 4 × 6 × 2 + 5 × 6 × 2 = 20 + 48 + 60, = 128 (square decimeter); a: to make such a water tank, it needs at least 128 square decimeters of iron sheet

There is a rectangular sheet of iron 12 decimeters long and 8 decimeters wide. My father plans to use this sheet of iron to surround the side of a rectangular water tank, and then match it with another one
A sheet of iron is used as the bottom to make a cuboid water tank without cover
1) Think about how many cuboid tanks can be made with different heights?
2) If dad wants to make a cuboid water tank with the largest volume, what should he do? How many square meters of iron sheet should he share?
3) How many liters of water can this tank hold at most?

1) 2) with the height of 12 decimeters, the bottom is square, the side length of the bottom is 8 ／ 4 = 2 (decimeters), the volume is 2 × 2 × 12 = 48 (cubic decimeters) = 48 liters, the height is 8 decimeters, the bottom is square, the side length is 12 ／ 4 = 3 (decimeters), the volume is 2 × 2 × 12 = 48 (cubic decimeters)

Factorization of (a + 2b) (a + 2b) - 4

5.25 times 7.8 plus 5.25 divided by 5

=5.25×7.8+5.25×(1/5)
=5.25×7.8+5.25×0.2
=5.25×(7.8+0.2)
=5.25×8
=(5+0.25)×8
=5×8+0.25×8
=40+2
=42

Whether there is a point P on the straight line y = 32x − 1, so that the circle centered on point P passes through two known points a (- 3,2), B (1,2). If there is, the coordinates of point P are obtained and plotted

Let the coordinates of point p be (x, 1.5x-1), ∵ PA = Pb, (x + 3) 2 + (1.5x − 3) 2 = (x − 1) 2 + (1.5x − 3) 2, 6x + 9 = - 2x + 1, then the coordinates of point P are (- 1, - 2.5)

7.5x-5x = 10 solution equation

2.5x＝10
x＝10÷2.5
x＝4

Given the set a = {(x, y) | y = x ^ 2}, B = {(x, y) | y = - x ^ 2 + m, m ∈ r}, find the intersection B of A

A to B
In fact, the solution of two equations
y=x^2
y=-x^2+m,m∈R
Sorting y = x ^ 2 = - x ^ 2 + M
2x^2=m
(1) When M0, the solution set is {(+ √ (M / 2), M / 2), (- √ (M / 2), M / 2)}

Using simple algorithm, (4 / 1 + 12 / 7) × 8 / 3 18 × 6 / 5-2 / 1 151 × 4 / 3-4 / 3 × 50-4 / 3

151×4/3-4/3×50-4/3
=(151-50-1)*4/3
=100*4/3
=400/3

If M + N0, there must be () a.m > 0, N0, n > 0 D.M

If M + N0, then M and n have the same sign,
So we can see that M0 D.M

A cuboid uncovered iron water tank is 0.8 meters long, 0.65 meters wide and 0.6 meters high. How many square meters of iron is needed to make this water tank? If each liter of water weighs 1 kg, how many kg of water can the tank hold at most? (the thickness of iron sheet is ignored)