Question

Срочно 50 баллов !!!!

Answer 1

Ответ: 1)

$an=-25.05\\an= a1+d(n-1)\\-25.05=1.35-2.4n+2.4\\2.4n=28.8\\n = 12$

2)

$\left \{ {{a1+2d=-3} \atop {a1+8d=-69}} \right. -\\\\-6d=66\\d=-11$