How to find if t linear transformation is invertable?

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

The vertices of a triangle are a(7,5), b(4,2), c(9,2). what is m

Satchi found a used bookstore that sells pre-owned dvds and cds. dvds cost $9 each, and cds cost $7 each. satchi can spend no more than $45.