SOLUTION: The roots of the equation x2+bx+c=0 where b and c are constants are –3 and 4. Find the values of b and c.

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Question 378680: The roots of the equation x2+bx+c=0 where b and c are constants are –3
and 4. Find the values of b and c.
Found 3 solutions by richard1234, solver91311, robertb:
Answer by richard1234(7193) About Me  (Show Source):
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A consequence of the fundamental theorem of algebra, if the roots of the polynomial are -3 and 4, then the polynomial becomes (x+3)(x-4). Expanding, this becomes x%5E2+-+x+-+12 so b = -1 and c = -12.

Answer by solver91311(24713) About Me  (Show Source):
You can put this solution on YOUR website!


If is a root of the equation , then is a factor of the polynomial .

Hence the two factors of your quadratic polynomial are and . If you multiply using FOIL, you will create the quadratic trinomial that you seek.

John

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Answer by robertb(5830) About Me  (Show Source):
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Since the coefficient of x%5E2 is 1, then the SUM of the roots is equal to the -b, while c is equal to the PRODUCT of the roots. Hence, -b = -3 + 4, or b = -1, while c = -3*4 = -12. =D