SOLUTION: Two numba ?*?=-5 and when added +5

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Question 1209774: Two numba ?*?=-5 and when added +5
Answer by ikleyn(52781) About Me  (Show Source):
You can put this solution on YOUR website!
.

Starting equations

    x *y =  -5     (1)
    x + y =  5     (2)


From equation (2), express  y = 5 - x and substitute it into equation (1).

    x*(5-x) = -5.


Simplify

    5x - x^2 = -5,

    x^2 - 5x - 5 = 0.


Solve quadratic equation using the quadratic formula

    x%5B1%2C2%5D = %285+%2B-+sqrt%285%5E2+-+4%2A1%2A%28-5%29%29%29%2F2 = %285+%2B-+sqrt%2845%29%29%2F2 = %285+%2B-+3%2Asqrt%285%29%29%2F2.


The numbers are  %285%2B3%2Asqrt%283%29%29%2F2 = 5.854101966 and  %285-3%2Asqrt%285%29%29%2F2 -0.854101966.    ANSWER


CHECK.  5.854101966*(-0.854101966) = -5.0000000000 with at least 10 decimals after the decimal dot.

Solved.