I need help with this please. there are other questions as well which i will add area of 2D SHAPES

When keisha installed a fence along the 200 foot perimeter of her rectangular back yard, she left an opening for a gate. in the diagram below, she used x to represent the length in feet of the gate? what is the value? a. 10 b. 20 c. 25 d. 30

Answer asap evaluate 4-0.25g+0.5h4−0.25g+0.5h when g=10g=10 and h=5h=5.

The perimeter of a rectangle is 42 inches. if the width of the rectangle is 6 inches, what is the length