100 - 80 = 20
80 = 72
20 = ?
72 / 80 = 0.9
20 x 0.9 = 180
180 + 72 = 252
Here we can change the variables to real numbers, just to make things easier for us. For the sake of calculation, let’s say that x=10, y=6, and z=1.
So, y years from now, Yann will be x years old. If we plug in our randomly chosen numbers, we get that Yann will be 10 years old 6 years from now. This means that today, he would be x-y years old, or 10-6, so 4 years old today.
Next we ask how old he was z years ago, or in this case, 1 year ago. We know that if you’re 4 years old now, you were 3 years old last year. In other words, you’re 4-1 years old, or x-y-z years old.
Your answer is x-y-z.
Alright - we want to start off by seeing if this number would be positive or negative. Debit means that you owe something, or that you have to pay that amount of money. If you had money to buy things with, that would be positive, but since debit means you haven’t paid something off yet, that is negative. Next, since you have 40 dollars in debt, you have -40 dollars.
Feel free to ask further questions!
Solution:
The three powers whose value is greater than 500 and less than 550 can be find by following procedure.
We will solve this problem by Hit and trial method by finding the squares, cubes, fourth power, Fifth Power,...etc. of different natural numbers.
23²= 529
8³ = 8 × 8 × 8 =512

The three powers are →→→Eighth power of 2, Square of 23, and Cube of 8.