Question

помогите с первым и вторым, пожалуйста с решением​

Answer 1

$\displaystyle\bf\\1)\\a_{1} =6\\\\a_{n+1} =a_{n} +6\\\\a_{2} =a_{1} +6=6+6=\boxed{12}\\\\d=6\\\\a_{4} =a_{1} +3d=6+3\cdot 6=\boxed{24}\\\\a_{11} =a_{1} +10d=6+10\cdot 6=\boxed{66}\\\\Otvet:12 \ ; \ 24 \ ; \ 66$

$\displaystyle\bf\\2)\\\\d=7\\\\a_{1} =1\\\\a_{n} =71\\\\\\a_{n} =a_{1} +d\cdot(n-1)\\\\71=1+7\cdot(n-1)\\\\71=1+7n-7\\\\7n=71+6\\\\7n=77\\\\Otvet:\boxed{n=11}$