For the first one, note that when you cross multiply, you get . This is now a quadratic equation which can easily be solved.

For the second one, note that when you cross multiply, you get . This is now a linear equation which can easily be solved.

For the third one, note that when you cross multiply, you get . This is now a quadratic equation which can easily be solved.

Can you try to continue on from where I left off in each problem?