-4(3m-3)+(-10+8m)
12m+12-1+8m
12m+8m = 20m
+12 -1= +11
answer: 20m+11
*note negative times a negative equals positive and negative times positive is negative
first: you multiply -4 by 3m which is -12m.
second: you multiply -4 by -3 which is +12
third: find the invisible which is 1. (located right here: +(1) (-10+8m)
fourth: multiply invisible 1 by -10 which is -10
fifth: multiply invisible one by +8m which is +8m
sixth: combine like terms
seventh: answer
Suppose we choose

and

. Then

Now suppose we choose

such that

where we pick the solution for this system such that

. Then we find

Note that you can always find a solution to the system above that satisfies

as long as

. What this means is that you can always find the value of

as a (constant) function of

.
The total cost of the meal will be $17.64.