What does variability mean? Can you give an example?

I am talking about MATH here guys!!!

Solve this equation using substitution. {4x + y = −2} {4x + 6y = 44}

If f(x) = 3x2 - 2x+4 and g(x) = 5x + 6x - 8, find (f-g)(x).

Adeli owner keeps track of the to-go orders each day. the results from last saturday are shown in the given two-way frequency table. saturday's to-go deli orders in person by phone online total pick up 38 25 31 94 delivery 35 28 34 97 total 73 53 65 191 what percent of the to-go orders were delivery orders placed by phone? a. 14.66% b. 38.41% c. 28.87% d. 52.83%