SOLUTION: P(x)=-x^2+6x+7 a. find x and y intercepts b. if this function represents the profit a company makes (in thousands of dollars), then find the maximum profit they can make sellin

Algebra ->  Quadratic Equations and Parabolas -> SOLUTION: P(x)=-x^2+6x+7 a. find x and y intercepts b. if this function represents the profit a company makes (in thousands of dollars), then find the maximum profit they can make sellin      Log On


   

Question 1126477: P(x)=-x^2+6x+7
a. find x and y intercepts
b. if this function represents the profit a company makes (in thousands of dollars), then find the maximum profit they can make selling x item.
Found 2 solutions by josmiceli, josgarithmetic:
Answer by josmiceli(19441) About Me  (Show Source):
You can put this solution on YOUR website!
y-intercept:
+P%280%29+=+0%5E2+%2B+6%2A0+%2B+7+
+P%280%29+=+7+
x-intercept;
+P%28x%29+=+0+
+x%5E2+%2B+6x+%2B+7+=+0+
complete the square
+x%5E2+%2B+6x+%2B+9+=+-7+%2B+9+
+%28+x+%2B+3+%29%5E2+=+2+
+x+%2B+3+=+sqrt%282%29+
+x+=+-3+-+sqrt%282%29+
+x+=+-3+%2B+sqrt%282%29+
( there are 2 x-intercepts )

Answer by josgarithmetic(39617) About Me  (Show Source):
You can put this solution on YOUR website!
----
P(x)=-x^2+6x+7
a. find x and y intercepts
----

The zeros are at -1 and 7.

-x%5E2%2B6x%2B7
-1%28x%5E2-6x-7%29
-1%28x%2B1%29%28x-7%29-------roots, -1 and +7.


Maximum P when x=3.