m is an unknown number that is being decreased by 7.
OPTION A IS WRONG BECAUSE MATHEMATICALLY IT IS WRITTEN AS

B IS WRONG BECAUSE IT MEANS

C IS WRONG BECAUSE IT MEANS

BUT D IS THE ANSWER BECAUSE IT MEANS

SINCE m IS TREATED AS AN UNKNOWN NUMBER.
GOODLUCK!!!!
Answer:
14.4h
Step-by-step explanation:
I assumed you meant 8h because 8 isn't a like term.
Answer:
x=61
Step-by-step explanation: