Mark M. answered 03/22/24
Retired math prof. Calc 1, 2 and AP Calculus tutoring experience.
dy/dx = (x + 5x2) / y4
y4dy = (x + 5x2)dx
∫ y4dy = ∫ (x + 5x2)dx
(1/5)y5 = (1/2)x2 + (5/3)x3 + C
Since y = 6 when x = 0, C = 1555.2.
y5 = (5/2)x2 + (25/3)x3 + 7776
So, y = [(5/2)x2 + (25/3)x3 + 7776]1/5