Ineed figuring out the fractions if not percent

What is the value of  y  in the solution to the system of equations? x  +  y  =  12x  –  3y  =  –30a. –8b. –3c. 3d. 8

Which function families have maximums and minimums? 1.)linear absolute value functions and exponential functions 2.) linear absolute value functions and quadratic functions 3.) linear absolute value functions and linear functions 4.) linear absolute value functions and constant functions

Molly shared a spool of ribbon with 12 people. each person received 3 feet of ribbon. which equation can she use to find r, the number of feet of ribbon that her spool originally had?