Question

номер 6-7 срочно!!!!!!"!

Answer 1

$6.;;a_1=3,;a_{n+1}=a_n+4Rightarrow d=4\a_10=a_1+9d=3+9cdot4=3+36=39\7.;;(a-3)^2-a(5a-6)=a^2-6a+9-5a^2+6a=-4a^2+9\a=-frac12Rightarrow-4a^2+9=-4left(-frac12right)^2+9=-4cdotfrac14+9=-1+9=8$