Keep doing each step manually, and see where it slips up:
−7.9+8.2−3.4+2.1=−1
−7.9+8.2+(−3.4)+2.1=−1
−7.9+(−3.4)+8.2+2.1=−1
(−7.9+(−3.4))+(8.2+2.1)=−1
−11.3+10.3=−1
You would have to find a common denominator
Let x be the capacity of the tank then
3x/4-x/8 =15,
then x=24, so so far it has 3/4 *24 =18 so you need 6 gallons to fill it up
Answer:
pi r squared divided by 2 for the half circle then add the area of the box to you number and there is your area
