Find the mistake in the below maths equations

A = 2
A(A-1) = 2(A-1)
A2-A = 2A-2
A2-2A = A-2
A(A-2) = A-2
A = 1

John replied, when asked how old he was. In 2 years he will be twice as old as he was five years ago.' How old is he ?

Three brothers Jacob, John, and James live in Mexico City. The product of the ages of these brothers is 175. Jacob and John are twins. How old is James?

If 21x = 79x, what is the value of x?

There is a square of a particular number which when doubled, becomes 7 more than its quarter.

Can you find the number?

How many people must be gathered together in a room, before you can be certain that there is a greater than 50/50 chance that at least two of them have the same birthday?

What will be the best approach to finding all the prime numbers less than 75 that leave an odd reminder when we divide them with 5?

Find three numbers such that When we multiply three numbers, we will get the prime numbers. The difference between the second and the first number is equal to the third and second.

You need to arrange three 7 and mathematical symbols to form number 1?

There is a straight highway. Four different villages lie on that highway. The distance between them is different. The third village is 60km away from the first village; the fourth is 40 km away from the second; the third is 10 km near to the fourth that it is to the second.

Can you calculate the distance between the fourth and the first village ?