Question 194613
first you have to rewrite this so that the variable y is positive and set this up to complete the square
:
{{{y=-1(x^2+4x)-3)}}}
:
{{{y=-1(x^2+4x+4)+4-3}}}
:
{{{y=-1(x+2)^2+1}}}
:
vertex is at (-2,1)
:
intercepts are found by setting y to zero
:
we know it opens down because it is in the form {{{y=x^2}}} and coefficient is a negative 1
:
{{{0=x^2+4x+3}}}--->{{{(x+1)(x+3)=0}}} so x intercepts are -1,-3: (-1,0)(-3,0)
:
{{{graph(300,300,-10,10,-10,10,-x^2-4x-3)}}}