The function of a parabola is y= ax² + b x c
If x' = -2 & x" = - 4 are the x intercepts then x= - 2 & x"= - 4 are the roots of this quadratic equation, we also know that this equation can be written as:
x² - Sx +P, where S= x' + x" (sum) & P = x' . x" (product), also we know (given) that x' = -2 & x" = - 4, hence, plug fpr S & P
x² - (-6) x + 8
===.> Y= X²+6X+8
& ITS AXIS OF SYMMETRY (-b/2a) ===> x= -3.
a is positive so it passes by a minimum (open up) Minimum (-3,-1)