What are the steps of getting from 20(y) = 20(3/4x) - 20(3/10) to 15x+20y=-6 ?

David bought a poster for an art project. the poster is 2.7 feet wide and 3.9 feet tall. what is the area of the poster?

Need ! give step by step solutions on how to solve number one [tex]\frac{9-2\sqrt{3} }{12+\sqrt{3} }[/tex] number two [tex]x+4=\sqrt{13x-20}[/tex] number three (domain and range) [tex]f(x)=2\sqrt[3]{x} +1[/tex]

What value of x is in the solution set of 4x – 12 s 16 + 8x?