Please tell me how to solve below 3 questions.

(choose answers; increasing, not relevant, decreasing, constant )

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determine where a function is increasing or decreasing without graphing the function.

When answering the question, first verify that the interval given is one of the relevant subintervals.

If it is not, select "Not relevant".

If it is one of your subintervals, answer whether the interval is increasing, decreasing, or constant.

1) f(x)=x21x24

(-infinity, 1) increasing, not relevant, decreasing, constant

(1, infinity) increasing, not relevant, decreasing, constant

(-infinity, infinity) increasing, not relevant, decreasing, constant

2)f(x)=x33x2+3x1

(-infinity, 1) increasing, not relevant, decreasing, constant

(1 , infinity) increasing, not relevant, decreasing, constant

(-infinity, infinity) increasing, not relevant, decreasing, constant

3)f(x)=x(x2)32

(- infinity, 0) increasing, not relevant, decreasing, constant

(-infinity,2) increasing, not relevant, decreasing, constant

(0,2) increasing, not relevant, decreasing, constant

(2,6) increasing, not relevant, decreasing, constant

(2, infinity) increasing, not relevant, decreasing, constant

(6,infinity) increasing, not relevant, decreasing, constant