SOLUTION: solve the equation, check the results graphically 3x2 + 9x + 1 = 0

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Question 394279: solve the equation, check the results graphically
3x2 + 9x + 1 = 0
Answer by ewatrrr(24785) About Me  (Show Source):
You can put this solution on YOUR website!


Hi

3x2 + 9x + 1 = 0

x+=+%28-b+%2B-+sqrt%28+b%5E2-4%2Aa%2Ac+%29%29%2F%282%2Aa%29+

x+=+%28-9+%2B-+sqrt%28+69%29%29%2F%286%29+ 

x is {-0.1156, -2.8844}

finding vertex by completing square

the vertex form of a parabola, y=a%28x-h%29%5E2+%2Bk where(h,k) is the vertex

y = 3(x^2 + 3) + 1

y = 3[(x+3/2)^2 - 9/4] + 1

y = 3(x + 3/2)^2 -23/4  Vertex is Pt(-3/2,-23/4)