SOLUTION: Hi! x+y=2 x*y=-15 Best regards Richard

Question 714545: Hi!
x+y=2
x*y=-15
Best regards
Richard
Answer by Simnepi(216) (Show Source): You can put this solution on YOUR website!
x+y=2 let's call this equation (1)
x*y=-15 let's call this equation (2)
from (1) we can deduce
y=2-x
let us substitute this value into (2)
giving us
x*(2-x)=-15
multiplying out the bracket gives

rearranging this gives

now we have a quadratic to solve!
(finding a factor pair of the constant term that will add to make the coefficient of the x term)
this gives
(x-5)(x+3)=0
and we find our numbers to be
5 and -3
thus x=5 and y=-3 (or vice versa!)
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