Question

Solve x = r2 - y2 for r.

Answer 1

ok .. so first add y2 on both sides i meant :
\[\large{x+y^2=r^2+y^2-y^2}\]

Answer 2

Thanks

Answer 3

my pleasure and also :
\[\Huge{\mathbb{Welcome}\textbf{To}\mathbb{OpenStudy}}\]

Answer 4

i think you did wrong some where:
\[\large{x^2+y^2=r^2-y^2+y^2}\]
\[\large{x^2+y^2=r^2-\cancel{y^2}+\cancel{y^2}}\]
\[\large{x^2+y^2=r^2}\]
\[\large{r=\sqrt{x^2+y^2}}\] your answer