What is the sum or difference of 3x ^ 8 - 7x ^ 8

Which function families have maximums and minimums? 1.)linear absolute value functions and exponential functions 2.) linear absolute value functions and quadratic functions 3.) linear absolute value functions and linear functions 4.) linear absolute value functions and constant functions

If the wwight of a package is multiplied by 7/10 the result is 65.8 find the weight of the package

What does independent variable and dependent variable mean in math?