Abag contains yellow marbles and red marbles, 31 in total. the number of yellow marbles is 1 less than 3 times the number of red marbles. how many yellow marbles are there?

What is the axis of symmetry of the function f(x)=-(x+ 9)(x-21)

60 musicians applied for a job at a music school. 14 of the musicians play both guitar and drums, 28 play drums, 18 play the guitar. what is the probability that the applicant who gets the job plays drums or guitar?

Mila's dog weighs 4 pounds more than 8 times the weight of keiko's dog. which expression could be used to fine te weight of mila's dog?