For each integral, determine which of the following techniques are useful to evaluate the integral. Find the technique (or method) that you need to use as the first step. Select one letter for each integral. x- +2x+3 dx x+1 (A) U Substitution (B) Integration by parts (C) Complete the square (D) Partial fractions (E) Long division (F) Trig substitution 2. dx x- -5x+6 (A) U Substitution (B) Integration by parts (C) Complete the square (D) Partial fractions (E) Long division (F) Trig substitution 1+x- (A) U Substitution (B) Integration by parts (C) Complete the square (D) Partial fractions (E) Long division (F) Trig substitution (A) U Substitution (B) Integration by parts (C) Complete the square (D) Partial fractions (E) Long division (F) Trig substitution 5 . fredx (A) U Substitution (B) Integration by parts (C) Complete the square (D) Partial fractions (E) Long division (F) Trig substitution