Will help with a couple... Please show any working so we know what you have done. I'll give you the answers as well but you'll need to some of your own working...

First question.

by expanding.

Then use .

ANSWER: 2

Second question.

Use the fact that and replace and with and .

ANSWER: (however this can be further simplified, I'll leave that up to you, use the hint in the next question)

Third question.

, hence for this question... so . Substitute in the equation.

ANSWER: