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10/5 , 11/2

Jun
18
2013
96,296 responses
Question of the Day Statistics
Number Answered
Correct 34,612
Incorrect 61,684
35% correct

Mathematics > Standard Multiple Choice

Read the following SAT test question and then click on a button to select your answer. 

y = (negative 2 times x^2) + (b times x) + 5

 

In the xy-plane, the graph of the equation above assumes its maximum value at x = 2. What is the value of b?

 

Answer Choices

Hint

Use the fact that y = (negative 2 times x^2) + (b times x) + 5 assumes its maximum value at x = 2 to write this quadratic equation in the form  y = a times ((x - h)^2) plus k.

Question of the Day

Can you answer today's question?

Register Next Tests:
10/5 , 11/2

Jun
18
2013
96,296 responses
Question of the Day Statistics
Number Answered
Correct 34,612
Incorrect 61,684
35% correct

Mathematics > Standard Multiple Choice

Read the following SAT test question and then click on a button to select your answer. 

y = (negative 2 times x^2) + (b times x) + 5

 

In the xy-plane, the graph of the equation above assumes its maximum value at x = 2. What is the value of b?

 

Answer Choices

Answer

Choice (D) is correct. Since the graph of the quadratic equation y = (negative 2 times x^2) + (b times x) + 5 assumes its maximum at x = 2, it can be written in the form  y = (negative 2 ((x minus 2)^2) + k, where k is some constant. This representation is equivalent to y = (negative 2 times x^2) + (8 times x) minus 8 + k, from which it follows that b = 8 (andnegative 8 + k = 5).