Answer:
The answer to your question is r = 10
Step-by-step explanation:
Data
(x² + 10x ) + (y² - 8y ) = 59
Process
1.- Complete the perfect square trinomials
(x² + 10x + (5)²) + (y² - 8y + (4)²) = 59 + (5)² + (4)²
2.- Simplify
(x² + 10x + 25) + (y² - 8y + 16) = 59 + 25 + 16
3.- Factor
(x + 5)² + (y - 4)² = 100
or (x + 5)² + (y - 4)² = 10²
4.- Compare the result with the standard form
(x - h)² + (y - k)² = r²
then r² = 10²
and r = 10
