Can someone me with my math finals later?

Four individuals pool money together to start a new business and agree to split the profits equally. n invests $6,000, x invests $2,000, y invests $8,000 and z invests $4,000. if the profits for the first month were $100,000, y receives than if the profits were divided in proportion to how much they invested.

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

What is the value of m in the equation 1/2 m - 3/4n=16 when n=8