Question

Find the equation of the quadratic function with zeros -8 and -2, "a" less than zero, and a vertex at (-5, 9).

Answer 1

Hello,

y=k(x+8)(x+2) and pass through (-5,9)
==> 9=k(3)(-3)==>k=-1

y=-(x+8)(x+2)=-(x²+10x+16)=-(x²+2*5x+25-25)-16
=-(x+5)²+25-16

y=-(x+5)²+9