Please help me with 5 thank you!

Simplify (a/b - b/a) times (a - a^2/a+b) a - a^2/a=b is a mixed number

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)

The fence around a quadrilateral-shaped pasture is 3a^2+15a+9 long. three sides of the fence have the following lengths: 5a, 10a-2, a^2-7. what is the length of the fourth side of the fence?