Answer:
Given that
x² + y² = 6xy
or, (x + y)² - 2xy = 6xy
or, (x + y)² = 8xy
or, (x + y)² = 2³xy
Taking (log) in both sides, we get
log (x + y)² = log (2³xy)
or, 2 log (x + y) = log (2³) + logx + logy
or, 2 log (x + y) = 3 log2 + logx + logy
Hope this helps :D