What's the least common denominator of 3⁄4, 4⁄5, and 2⁄3?

a. 20
b. 12
c. 60
d. 15

Math it's appreciated. (picture provided)

What is the solution to the system of equation graphed belowa.(0,-4)b.(2,5),1),-3)

From the top of a tree a bird looks down on a field mouse at an angle of depression of 50°. if the field mouse is 40 meters from the base of the tree, find the vertical distance from the ground to the bird's eyes.