We’ll use the given information to create a quadratic polynomial so we can find the axis of symmetry:
(x+7)(x)
FOIL:
(x•x)+(7•x)
x^2+7x is the quadratic trinomial in standard form.
Now, recall the axis of symmetry formula:
x=-b/2a
Now that the quadratic is in standard form, let’s define a and b:
a=1
b=7
Input a and b into the formula:
x=-(7)/2
x=-3.5
Therefore, the axis of symmetry is the line x=-3.5