Question

a10 = 33
S8 = 88
a1 - ?
d - ?
дуже потрібна допомога

Answer 1

$a_1+9d=33 to a_1=33-9d \ \ frac{2(33-9d)+7d}{2}*8=88 \ (2(33-9d)+7d)*4=88 \ 66-18d+7d = 22 \ -11d=-44 \ d=4 \ \ a_1=33-9d=33-9*4=33-36=-3$