Plz answer this step bye step.
20-(-30)+(-15)÷3
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Measure of angles 31 (x+4) (3x+9) me

This is a rational expression because the denominator contains a variable. this is a polynomial with 3 terms. this is a rational expression because the denominator contains a variable. this is a polynomial with 4 terms. this is a rational expression because the denominator contains a variable. this is a polynomial with 4 terms. this is a rational expression because the denominator contains a variable. this is a polynomial with 3 terms. this is a rational expression because the denominator contains a variable. this is a polynomial with 5 terms.

Either enter an exact answer in terms of \piπ or use 3.143.14 for \piπ and enter your answer as a decimal.