The daily cost of hiring a plumber, y, to work hours on a repair project can be modeled
1 answer:
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Answer:
Step-by-step explanation:
Method 1
we know that
The equation of a vertical parabola in vertex form is equal to
where
a is the leading coefficient
(h,k) is the vertex
we have
(h,k)=(-1,-9)
substitute
Remember that
one root is (-7,0)
substitute and solve for a
therefore
Method 2
I use the fact that the roots are the same distance from the vertex
the distance from the given root to the vertex is equal to
6 units
so
If one root is x=-7
then the other root is
x=-1+6=5
The general equation of the quadratic equation is equal to
we have the vertex (-1,-9)
substitute the value of x and the value of y and solve for a
so
Expanded the equation, complete the square and rewrite as vertex form