NYT whats going on in this graph

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?

Which expression is equivalent to (9x - 3 1/ + 1 3/8)

Write the sentence as an equation. z plus 372 is equal to 160