г) 1/9х2 + 2/15xy + 1/25y2 = (1/3x)^2 + 2/3xy + (1/5y)^2 = (1/3x + 1/5y)^2
д) 100b2 + 9с2 - 60bс = (10b - 3c)^2
е) 49х2 + 12ху + 64y2 = (7x)^2 + 27x4y + (8y)^2 = (7x + 8y)^2
г) 1/9х2 + 2/15xy + 1/25y2 = (1/3x)^2 + 2/3xy + (1/5y)^2 = (1/3x + 1/5y)^2
д) 100b2 + 9с2 - 60bс = (10b - 3c)^2
е) 49х2 + 12ху + 64y2 = (7x)^2 + 27x4y + (8y)^2 = (7x + 8y)^2