Question

The difference between the roots of the quadratic equation x2 -14x +q =0 is 6. Find q

Answer 1

9514 1404 393

Answer:

  q = 40

Step-by-step explanation:

When the quadratic has roots p and r, it can be factored as ...

  (x -p)(x -r) = x² -(p+r)x +pr

So, the sum of the roots is 14, and their difference is 6. This lets us find the roots from ...

  p + r = 14

  p - r = 6

  2p = 20 . . . add the two equations

  p = 10

  r = 14 -p = 4

The value of interest is then ...

  q = pr = (10)(4)

  q = 40

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The graph shows the roots to be 4 and 10, as we found.