The equation;
[tex]\begin{gathered} \text{Given the equation; y=3x}^2+30x+71 \\ we\text{ have,} \\ y=3(x^2+10x)\text{ + 71} \\ y=3(x+5)^2-25+71 \\ y=3(x+5)^2+46 \\ \\ \text{Hence, the missing values in the box are respectively 5 and 46} \end{gathered}[/tex]Also, the extreme values of the equation are (5, 46)