Question

a1 = -3; a2 = 4; a16 - ?

Answer 1

Ответ:

решение смотри на фотографии

Answer 2

$\displaystyle\bf\\a_{1}=-3\\\\a_{2} =4\\\\a_{2} =a_{1}+d\\\\d=a_{2} -a_{1} =4-(-3)=4+3=7\\\\a_{16} =a_{1} +15d=-3+15\cdot 7=-3+105=102\\\\Otvet: \ a_{16} =102$