An=A1+(n-1)*d
A12=-5.6+11*(-1.2)=-5.6-13.2=-18.8
=7²=49
по основному лог. тождеству
<span>(10√24-√54)×√6=(20</span>√6-3√6)*√6=120-18=102<span>
(√6-√8):√2=(</span>√3√2-2√2)/√2=√3-2<span>
(3+√5)(√5-4)=3</span>√5-12+5-4√5=-√5-7<span>
(√x-5)(√x+5)=x+5</span>√x-5√x-25=x-25<span>
(√11-√6)²=11-2</span>√11√6+6=17-2√11√6=17-2√66<span>
(√7+2√3)²=7+4</span>√7√3+12=19+4√21<span>
(√2-1)(2+√2+1)=2</span>√2+2+√2-2-√2-1=2√2-1=√8-1