Answer:
x > -3
Step-by-step explanation:
The function will be increasing where its derivative is positive.
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y = x^2 +6x . . . . . given function
y' = 2x +6 . . . . . . . derivative
The derivative is positive for ...
2x +6 > 0
2x > -6
x > -3 . . . . . domain where the function is increasing
