Question 50513
P(x)= -x^2+40x+825
Rewrite as follows:
-(x^2-40x+?)= P(x)-825+?
Complete the square to get:
-(x^2-40x+400) = P(x)-825-400
-(x-20)^2 = P(x)-425
This follows the form y-k=(x-h)^2
where (h,k) is the vertex.
For your problem h=20,k=425
Vertex is (20,425).
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To find the y-intercept let x=0 in the original equation.
Then P(0)=825.
So, y-intercept is (0,825)
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To find the x-intercepts use the quadratic formula.
Cheers,
Stan H.