Subtract (x^2+5--3x-7) explain each step

How many grams the dog will eat in 3 days?

The input to the function is x and the output is y. write the function such that x can be a vector (use element-by-element operations). a) use the function to calculate y(-1.5) and y(5). b) use the function to make a plot of the function y(x) for -2 ≤ x ≤ 6.

Yvaries directly as x. y =90 when x=6. find y when x=13