Question

What is the axis of symmetry for the graph `y= -x^2-8x+10`?

Answer 1

`x=-4`

Explanation:

`"the axis of symmetry passes through the vertex and has "`
`"equation"`

`•color(white)(x)x=c`

`"where c is the value of the x-coordinate of the vertex"`

`"for a parabola in standard form "ax^2+bx+c`

`x_(color(red)"vertex")=-b/(2a)`

`y=-x^2-8x+10" is in standard form"`

`"with "a=-1,b=-8,c=10`

`rArrx_(color(red)"vertex")=-(-8)/(-2)=-4`

`rArr"axis of symmetry is "x=-4`
graph{(y+x^2+8x-10)(y-1000x-4000)=0 [-80, 80, -40, 40]}