Answer
midline: $y=7$
period = $2$
amplitude = $2$
Work Step by Step
Rewrite the equation by dividing by $6$ to get $$y=\frac{12}{6}\sin(\pi t -7)+\frac{42}{6}$$ $$y=2\sin(\pi t -7)+7$$ Equate this equation to the formula $$y=A\cos(B(t-h))+k$$ where $|A|$ is the amplitude, $2\pi/|B|$ is the period, and the midline is $y=k$. Using this form for the equation gives amplitude equal to $|2|=2$, period equal to $2\pi/\pi=2$, and midline $y=7$.
