Evaluate: 3t^2+6t+3

Expression: $3{t}^{2}+6t+3$

Factor out $3$ from the expression

$3\left( {t}^{2}+2t+1 \right)$

Use ${a}^{2}+2ab+{b}^{2}={\left( a+b \right)}^{2}$ to factor the expression

$3{\left( t+1 \right)}^{2}$