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# Help plz

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Find all values of b for which the equations 1988x^2 + bx + 8891 = 0 and  have a common root.

Enter all the possible values of b separated by commas.

Sep 3, 2019

$$\text{A quadratic has a common root when it's discriminant is 0}\\ p(x) = a x^2 + bx+c \Rightarrow D = b^2 - 4ac\\ D = b^2 - (4)(1988)(8891) = 0\\ b^2 = 70701232\\ b = \pm 4 \sqrt{4418827}$$