Justin ate 2/3 of pie, and joey ate 1/4 of the pie. how much of the pie is left?

I’m stuck on this i don’t understand.

Me solve this problem, and someone clearly explain to me how to solve it.1.) use the value of the discriminant to determine if the given trinomials has 2 real solutions, 1 real solution, or no real solutions.a.  x2  − 4x  − 7 = 0b. 4r2  + 11r  − 3 = 0c. 3m2  + 7 = 0d.  t2  + 2t  + 1 = 0

Lucy and donavan measured the length of the school garden. lucys measurement is 11.3m and donavans measurement is 113 cm. could both be correct? explain