Need now! use the substitution method to solve the system of equations. choose the correct ordered pair. x+y=12 -x=-y-10

Will mark brainliest question in the pic.

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?

Find the zeros of each function. f(x) = x^2 + 5x - 6