Find b such that f(x) and g(x) intersect at one point only.

f(x) = 3x^2 + 5x + 7

g(x) = bx + 3

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I set them equal

3x^2 + 5x + 7 = bx + 3

3x^2 + (5-b)x + 4 = 0

-(5-b) + - sqrt b^2 - 10b + 25 - (48)

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6

-5 + b + - sqrt b2 -10b -23 / 6 I don't know what to do next the answer is suppose to be 5 + - 4 sqrt 3

How did they get rid of the "b" in the sqrt

I would love some help

Thanks,

Marion