Question 936233
step 1 : determination of vertex
 {{{ y= -2x^2-12x-10}}}
 {{{ y= -2(x^2+6x+5)}}}
 {{{ y= -2(x^2+2*x*3+3^2-4)}}}
 {{{ y= -2((x+3)^2-4)}}}
  {{{ y= -2(x+3)^2-2(-4)}}}
 {{{ y= -2(x+3)^2+8 }}}
  vertex form   {{{  y=a(x-h)^2+k}}}
  vertex   =(h,k)
  hence vertex  (h,k) =(-3,8)
step 2
determination of y-intercept:
 keep x=o in the  y= -2x^2-12x-10
                 y= -2*0-12*0 -10
           y= -10 
 hence y-intercept  = -10

step 3
Determination of x-intercept:
keep y= 0 in  y= -2x^2-12x-10
          {{{ 0= -2x^2-12x-10}}}
         *[invoke quadratic "x", -2, -12, -10 ]
             
hence x-intercepts are -5,  -1