Question 1015652
Find the x-value for the vertex and that is the axis.
x=-b/2a, where b is 7 and a is 1
The vertex has an x-value of -7/2.  You don't even need the y-value.  The axis of symmetry is x=-3.5
{{{graph(300,200,-10,10,-10,10,x^2+7x+6)}}}