Is there a answer key for 28a angles of triangles

Quick translate "x is 12 units from 20" into an equation. what are the values of x being described? if you can answer any of my other questions that'd be great too

Martin likes to make flower bouquets that have 3 daffodils and 4 tulips per vase. a daffodil has a mass of d grams, a tulip has a mass of t grams, and the vase has a mass of u grams. the expression 5(3d + 4t + v) describes the mass of 5 bouquets. match each amount in the situation with the expression that represents it. situation expression number of bouquets mass of one bouquet mass of the tulips in one bouquet 4t mass of the daffodils in one bouquet 3d + 4t + v

Which math sentence can be used to determine if the triangle is a right triangle?