What is the least common denominator of 11/12 and 9/8

The equation x2 – 1x – 90 = 0 has solutions {a, b}. what is a + b?

Yahir designs bracelets. he uses between 9 and 15 red and yellow beads in the ratio of 2 red bead to 5 yellow beads. drag the beads into the container to meet these requirements

Tom can paint the fence in 12 hours, but if he works together with a friend they can finish the job in 8 hours. how long would it take for his friend to paint this fence alone?