Question 714545
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
{{{2x-x^2=-15}}}
rearranging this gives
{{{x^2-2x-15=0}}}
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!)