y' = 3e^y + xe^y

dy/dx = e^y(3 + x)

e^-y dy = (3 + x) dx

Integrating both sides:

-e^-y = 3x + x²/2 + C

-y = ln|-3x - x²/2 + C|

y = -ln|-3x - x²/2 + C|

0 = -ln(C)

C = 1

y = -ln|-3x - x²/2 + 1|

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