Answer:
[tex]x^2+y^2=34[/tex]
Step-by-step explanation:
Expand [tex](x+y)^2[/tex].
[tex](x+y)^2=x^2+2xy+y^2[/tex]
[tex]x^2+2xy+y^2=64[/tex]
Substitute 15 for xy.
[tex]x^2+2(15)+y^2=64\\\\x^2+30+y^2=64\\\\x^2+y^2=34[/tex]
