What is the value of 9x - 4y if x=3 and y=2

Hi, can anyone show me how to do this problem? 100 points for this. in advance

Evaluate the discriminant of each equation. tell how many solutions each equation has and whether the solutions are real or imaginary. x^2 - 4x - 5 = 0

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?