Let's use the variable y to represent the amount of calories burned.
For routine #1, we can write the equation:
[tex]y_1=8.5\cdot t[/tex]For routine #2, we have:
[tex]y_2=17+4.25\cdot t[/tex]If routine #1 will burn more calories, we have the inequality:
[tex]\begin{gathered} y_1>y_2 \\ 8.5t>17+4.25t \\ 8.5t-4.25t>17 \\ 4.25t>17 \\ t>\frac{17}{4.25} \\ t>4 \end{gathered}[/tex]So for t > 4 (more than 4 minutes running) the routine #1 will burn more calories than routine #2.