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

I am a word that begins with the letter “i.” If you add the letter “a” to me, I become a new word with a different meaning, but that sounds exactly the same. What word am I?

Solve the following series:
AZ, GT, MN, __, YB

In the image given, you can find several triangles. Can you count them all?

There is a place where if I stand up straight, I will still be considered sideways.

I have cities, but no houses. I have mountains, but no trees. I have water, but no fish. What am I?

What does below chemistry rebus means?

Bay of Bengal is in which state?

Mr Red Lives in the red house.
Mr Green Lives in the greenhouse.
Mr Yellow Lives in the yellow house.

Who lives in the Whitehouse?

Only one colour, but not one size,
Stuck at the bottom, yet easily flies.
Present in sun, but not in rain,
Doing no harm, and feeling no pain.
What is it?