Browse · MATH Print → jmc algebra junior Problem What is the greatest possible value of x+y such that x2+y2=90 and xy=27? Solution — click to reveal We have (x+y)2=x2+y2+2xy=90+2⋅27=144, so x+y=12 or x+y=−12. We want the larger value, or x+y=12. Final answer 12 ← Previous problem Next problem →