Ad=f solve for a. how would i do this and were would i start

The amount cami raised during last year’s charity walk, $45.50, is 7/10 of the amount she raised this year. which equation represents n, the number of dollars she raised this year?

3/4 = c/36 i need with this fraction proble.

What are the solutions of the equation x4 – 5x2 – 14 = 0? use factoring to solve. someone !