Evaluate this -4-12/(-4)?

Given the two similar triangles, how do i find the missing length? if a=4, b=5, and b'=7.5 find a'

Which best describes the function on the graph? direct variation; k = −2 direct variation; k = -1/2 inverse variation; k = −2 inverse variation; k = -1/2

How does the graph of y = 3x compare to the graph of y = 3-x?