Please someone help me on these 4 questions. Please don’t put a link. Please someone help me.

30 pts, will mark brainliestwhat is the period of the sinusoidal function? (picture 1)what is the minimum of the sinusoidal function? (picture2)what is the maximum of the sinusoidal function? (picture 3)

Write the fraction 9/50 as a decimal if needed round to the nearest hundredth

To solve the system of equations below, grace isolated the variable y in the first equation and then substituted into the second equation. what was the resulting equation? 3y=12x x^2/4+y^2/9=1