in a test +3 marks are given for every correct answer and -1 for every incorrect answer Mary attempted all questions and scored
1 answer:
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Answer:
The correct options are;
Answer to A1 is D
Answer to A2 is D
Answer to A3 is D
Answer to A4 is D
Answer to A5 is D
Answer to A6 is D
Answer to A7 is D
Answer to A8 is D
Answer to A9 is D
Answer to B1 is I
Answer to B2 is I
Answer to B3 is I
Answer to B4 is I
Answer to B5 is I
Answer to B6 is I
Step-by-step explanation:
The given function is f(x) = 9·x² + 54·x - 66
The extremum of the function are found as follows;
d(f(x))/dx = 0 = d(9·x² + 54·x - 66)/dx = 18·x + 54
∴ 18·x + 54 = 0 at the maximum or minimum points
x = -54/18 = -3
Given that d²(f(x))/dx² = 18 > 0. x = -3 is a minimum point
Given that the function is a quadratic function, we have;
1) Points to the left of x = -3 are decreasing
2) Points to the right of x = -3 are increasing.
