SOLUTION: The graph of a quadratic function y = g(x) is shown and f(x) = 3x2 + bx + c. If the graph of g(x) is reflected over the y-axis then the new graph will have the same line of symmetr

Algebra ->  Trigonometry-basics -> SOLUTION: The graph of a quadratic function y = g(x) is shown and f(x) = 3x2 + bx + c. If the graph of g(x) is reflected over the y-axis then the new graph will have the same line of symmetr      Log On


   

Question 1179006: The graph of a quadratic function y = g(x) is shown and f(x) = 3x2 + bx + c. If the graph of g(x) is reflected over the y-axis then the new graph will have the same line of symmetry as f(x). Find the value of "b" that makes this true. A) -3 B) -6 C) 3 D) 6
Found 2 solutions by greenestamps, ikleyn:
Answer by greenestamps(13200) About Me  (Show Source):
You can put this solution on YOUR website!


no graph of g(x) is shown

Answer by ikleyn(52803) About Me  (Show Source):
You can put this solution on YOUR website!
.

            It seems to me that I do understand your request.

            Look attentively for my steps. 


f(x) has the (vertical) axis of symmetry  x = -b%2F2a = -b%2F%282%2A3%29 = -b%2F6.


It means that g(x) has the (vertical) axis of symmetry  x = %2Bb%2F6.


Now, from your graph, you, the visitor,  SHOULD SEE  that axis of symmetry for g(x),

so you can restore the value of  b%2F6 first, and then the value of "b" itself.


In short terms,  the symmetry axis for  g(x)  is the mirror reflection of the symmetry axis of  f(x)  relative the  y-axis.


It means that  b-value for  g(x)  is the opposite number to the  b-value of  f(x).


That is all.  Quite obvious.


Solved,  answered and explained.