The sequence {an} satisfies: A1, a2-a1, a3-a2 , an-an-1 form an equal ratio sequence with 2 as the first term and 3 as the common ratio

The sequence {an} satisfies: A1, a2-a1, a3-a2 , an-an-1 form an equal ratio sequence with 2 as the first term and 3 as the common ratio

a1=2
a2-a1=2*3
a3-a2=2*3^2
.
an-a(n-1)=2*3^(n-1)
The sum of the above is as follows:
an=2(1+3+...+3^(n-1))=3^n-1

Solve the equation √ (x-1) + √ √ (2-x) = 1 (√ √ is a cubic root)

Solve the equation √ (x-1) + √ √ (2-x) = 1 (√ √ is a cubic root)
x=1
x=2

It takes 10 hours for a large truck to transport a pile of coal alone, and 15 hours for a car to transport it alone. Now two cars transport this batch of coal at the same time, and it takes 6 hours to transport it, and it takes a long time to transport it
180 tons of coal were transported by truck. How many tons of coal are there in total?

Truck efficiency: Car efficiency = 1 / 10:1 / 15 = 3:2
Truck per hour = 180 ÷ 6 ÷ (3-2) × 3 = 90 tons
Total = 90 × 10 = 900 tons

There was a pile of coal, originally planned to be transported by car, 1.2 tons each time, which was just finished seven times?
There was a pile of coal, which was originally planned to be transported by car, 1.2 tons per time, 7 times just finished. Later, it was transported by truck, 2 times just finished. The truck had a pile of coal for every% d% a than the minivan, which was originally planned to be transported by car, 1.2 tons per time, 7 times just finished. Later, it was transported by truck, 2 times just finished. How many tons more was transported by truck than minivan each time?

7 * 1.2 = 8.48.4 / 2 = 4.24.2-1.2 = 3 tons