Question

qual a pa em que o terceiro termo vale 13 e o sexto vale 22

Answer 1

a1+2r=13 (-1)          -a1-2r=-13

a1+5r=22                  a1+5r=22

                                -----------------

                                    3r=9

                                     r=9/3

                                     r=3

a1+2r=13

a1=13-2r

a1=13-2.3

a1=13-6

a1=7

PA=(7,10,13,16...)