USING STRUCTURE For what value of $a$ are the graphs of $6y=-2x+4$ and $2y=ax-5$ parallel? perpendicular?

I'll give brainliest if you answer right : )

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?

A) find the derivative of the inverse to f(x) = 3x + sint at x 6. b) (cale) find the derivative of the inverse to f(x)+3sin at x 6. if x +2y -34, ind he behaviar of the cure at 4,.3), c) a. increasing, concave up d. decreasing, concave down b. increasing, concave down e. decreasing, inflection point c. decreasing, concave up