3(x+3)=30 i have literally forgotten everything about algebra

Lilianna uses 3/4 calories per minute just by sitting. she uses 1 more calorie per minute by walking. lilianna uses a total of 12 1/4 calories walking to the park. lilianna uses the equation, d(.75+1)=12.25 to represent the situation. what does the variable d represent in the equation?

In each bouquet of flowers, there are 2 roses and 3 white carnations. complete the table to find how many roses and carnations there are in 2 bouquets of flowers.

In the diagram below? p is circumscribed about quadrilateral abcd. what is the value of x