SOLUTION: find the value of b such that the vertex of parabola y = x² + bx +c lies on y-axis

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Question 1106931: find the value of b such that the vertex of parabola y = x² + bx +c lies on y-axis
Answer by ikleyn(52803) About Me  (Show Source):
You can put this solution on YOUR website!
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Answer. b = 0.


Solution 

    x-coordinate of the vertex is -b%2F%282a%29.


    The fact that the vertex lies at the y-axis means that x-coordinate of the vertex is zero,  or, in other words, -b%2F%282a%29 = 0.


    It implies  b = 0.

Solved.