What is the x-value of the vertex of f(x) = -x2 + 9x - 11 ?

Amovie streaming service charges it’s customers $15 a month. martina has $98 saved up. will she have any money left over if she pays for the maximum amount of months she can afford? explain.

Does anyone know how to solve and graph this: 4 + | a + 2 | < 7the only part i don't get is the "4 +"

Wrote and expression for the difference of p and 4