Solve each system by substitution 2x + y = 20 and 6x - 5y = 12

What are the soultion(s) to the quadratic equation 40- x^2=0

Tom had a total of $220 and he spent $35 on a basketball ticket . what percent of his money did he have left?

Last year, a state university received 3,560 applications from boys. of those applications, 35 percent were from boys who lived in other states. part a)how many applications did the university receive from boys who lived in other states? part b)applications to the university from boys represented 40percent of all applications. how many applications did the university receive in all? i don't how to do part b so me and plz tell how you got your answer