SOLUTION: Please help me with this : f(x)=8x^2+6 and g(x)=6x+a, find a so that the graph of f of g crosses the y-axis at 78
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Question 823661: Please help me with this : f(x)=8x^2+6 and g(x)=6x+a, find a so that the graph of f of g crosses the y-axis at 78 Answer by stanbon(75887) (Show Source):
You can put this solution on YOUR website! Please help me with this : f(x)=8x^2+6 and g(x)=6x+a, find a so that the graph of f of g crosses the y-axis at 78
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fog(x) = f[g(x)] = f[6x+a] = 8(6x+a)^2+6
= 8(36x^2+12ax+a^2)+6
= 288x^2 + 96ax + 8a^2+6
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Solve for "a" based using (0,78)
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78 = 0 + 0 + 8a^2+6
8a^2 = 72
a^2 = 9
a = 3 or a = -3
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Cheers,
Stan H.
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