SOLUTION: The parabola defined by the equation y=x squared -10x+26 is shifted three units downward. If the new line of symmetry is x=-3 ,and the value of a=2,what is its new equation?

Algebra ->  Parallelograms -> SOLUTION: The parabola defined by the equation y=x squared -10x+26 is shifted three units downward. If the new line of symmetry is x=-3 ,and the value of a=2,what is its new equation?       Log On


   



Question 1091491: The parabola defined by the equation y=x squared -10x+26 is shifted three units downward. If the new line of symmetry is x=-3 ,and the value of a=2,what is its new equation?

Answer by Edwin McCravy(20060) About Me  (Show Source):
You can put this solution on YOUR website!
y+=+x%5E2-10x%2B26

The vertex of the original equation has x-coordinate -b/(2a) = -(-10)/(2*1) = 5
so the axis of symmetry of the original equation is x=5.  So it must be
shifted 8 units left to go left to x=-3. We are given that it is shifted 3
units down and since the new value of "a" is to be 2 and not 1, it must also
be stretched by a factor of 2, otherwise "a" would remain 1.  So we replace
x by x-8, multiply the right side by 2 to stretch so that a=2, then subtract
3 to shift down 3 units, so the translated equation is

y+=+22%28%28x%2B8%29%5E2-10%28x%2B8%29%2B26%29-3

which simplifies to  

y=2x%5E2+%2B+12x+%2B+17

[However if we shift down 3 before we stretch to make a=2, the answer
will be 

y+=+2%28%28x%2B8%29%5E2-10%28x%2B8%29%2B26-3%29

which simplifies to  

y=2x%5E2+%2B+12x+%2B+14

Edwin