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

Can you solve this picture maths equation?

A train leaves from point A for point B at 80 mph. After half an hour, another train leaves from point B for point A at 60 mph.

Which of the trains will be farther from point A when they meet ?

What type of tree can I carry in my hand?

What 4-letter word can be written forward, backward or upside down, and can still be read from left to right?

What has many teeth, but cannot bite?

My thunder comes before the lightning; my lightning comes before clouds; my rain dries all the land it touches. What am I?

Solve the equation in the image by looking at the pattern closely.

John was writing his first book. After saving the document, he locked his laptop with a password and mentioned some phrases for the hint box.

A friend of his tried opening his laptop but found out that it was password protected. Following is the hint that appeared.
1 mobile 3 books 2 roars 1 night 4 balls 2 lighters 1 ghost 1 hat 3 watches.

Can you help him in cracking the password?

Look at the picture and find out which square is not linked with any of the other squares.