(2a-b of a + B - B of a-b) / / a-2b of a + B

(2a-b of a + B - B of a-b) / / a-2b of a + B

There is piping at the Bank of the river, and the river water continuously flows to a dry pond on the bank. Assuming that the amount of water gushed out every minute is the same, if two pumps are used to pump water, the water in the pond can be pumped out in 40 minutes; if four pumps are used to pump water, the water in the pond can be pumped out in 16 minutes; if the water in the pond is pumped out in 10 minutes, at least how many pumps are needed?

Suppose that a cubic meter of water has been gushed out from the pipeline before pumping, B cubic meter of water is gushed out from the pipeline every minute, and C cubic meter of water can be pumped out from each pump every minute, then according to the meaning of the question: a + 40B = 2 × 40Ca + 16b = 4 × 16C, the solution is: a = 1603cb = 23C, if the water is to be pumped out in 10 minutes, at least

Calculation or simplification
（1）（ 1/3√27-√24-3√2/3）×√12
（2）2/b√ab5×（-2/3√a3b）÷（3√b/a）(a＞0,b＞0)
solve equations
（3）3（x-2）²=x(x-2)
（4）2x²-5x+1=0
(2) Where is the fifth power of B and the third power of A

1. The original formula = [1 / 3 √ (3 × 9) - √ (4 × 6) - 3 √ 2 / √ 3] × √ 12
=(√3-2√6-√6)×√12
=(√3-3√6)×√12
=√3×√12-3√6×√12
=√36-3√72
=6-18√2
2. The original formula = 2 / b × √ a × B & sup2; × √ B × (- 2 / 3 √ a3b △ 3 √ B / a)
=2b√ab×[-2/9×√(a3b×a/b)]
=2b√ab×(-2√3a²/9）
=-4b√3a²b/9
=-4ab√3b/9
3.3(x²-4x+4)=x²-2x
3x²-12x+12=x²-2x
2x²-10x+12=0
x²-5x+6=0
x²-5x+25/4=1/4
(x-5/2)²=1/4
x-5/2=1/2
x=3
4.x²-(5/2)x+1/2=0
x²-(5/2)x+25/16=17/16
(x-5/4)²=17/16
x-5/4=√17/4
x=(5+√17)/4