Question 1002668
y=-4x^2-18x+5
y-5=-4(x^2+9x/2)
Complete the square
y-5= -4(x^2+(9x/2)+81/16)+(81/4), subtracting (-4)(81/16) from one part, must add it back.

y= -4{x+(9/2)^2}+25(1/4)
check by the vertex h=-b/2a and k=f(h).  Vertex x=value is 18/-8=-2.25, and the y-value is 25.25


{{{graph(300,200,-10,10,-25,30,-4(x+(9/2))^2+25.25)}}}