What is the axis of symmetry of the function f(x)= -(x + 9)(x - 21)

Tod does not have any cookies. david gives jeff 8 cookies. then he splits half of the cookies he has left with tod. david let’s c represent the number of cookies that he starts with. he finds the number of cookies that tod has is 1/2 the difference of c and 8. write an expression to represent the number of cookies that tod has.

What is the equation of the line that is parallel to the line with the equation y= -3/4x +1 and passes through the point (12,-12)

Which equation is y = -6x2 + 3x + 2 rewritten in vertex form?