X=number of gallons that she must order.
4 gallons-----------------3 weeks
(7 gallons + x)--------12 weeks
We solve this rule of 3.
(7 gallons +x)3 weeks=4 gallons*12 weeks
21 gallons weeks+3 x weeks=48 gallons weeks
3x weeks=48 gallons weeks - 21 gallons weeks
3x weeks=27 gallons weeks
x=(27 gallons weeks) / 3 weeks=9 gallons.
Solution: she must order 9 gallons more.
Answer:
Square. If the middle is 90° then all of them have to be.
The correct answer is -15 because the absolute value is 15 but there is a negative outside the absolute value lines making it negative :)