<span>x(t)=-t^2+8t-21
v=</span><span>x</span>⁾<span>(t)=(-t^2+8t-21)</span>⁾ =-2t+8
v(3)=-2*3+8= 2 м/c
Под первым корнем получается 2.
2+ 3*(2/3)= 2+2=4
<span>1)2√3(√12+3√5) -√5(6√3-√20)=2√36+6√15-6√15+√100=12+10=22</span>
<span><span>2)√6(0,5√24-8√11) - 4√11(√99-2√6)=0.5√144-8√66-4√1089+8√66=0.5*12-4*33=6-132=-126</span></span>
<span><span><span>3)(√162-10√5)√2 + (5+√10)² =√324-10√10+25+10√10+10=18+25+10=53</span></span></span>