Question 1210340
{{{system(x+y=10,and,xy=-16)}}}


{{{y=10-x}}}.
Substitute...
{{{x(10-x)=-16}}}

{{{10x-x^2=-16}}}

{{{-10x+x^2=16}}}

{{{x^2-10x-16=0}}}


General Solution for Quadratic Equation

{{{x=(10+- sqrt(100+4*16))/2}}} (some steps taken, not shown)

{{{x=(10+- sqrt(164))/2}}}

{{{x=(10+- sqrt(4*41))/2}}}

{{{x=5+- sqrt(41)}}}


and you can finish what this means.