Question

$<var>(t+3)^{2}-(6t-1) </var>$            при t=2\sqrt{7}

Answer 1

$<var>(t+3)^{2}-(6t-1)=(t^2+6t+9)-(6t-1)=t^2+10=(2\sqrt7)^2+\\+10=28+10=38</var>$