Combining the operations
The allowed operations are:
Add the same amount to both sides (either x's or ones)
Subtract the same amount from both sides (either x's or ones)
Multiply both sides by the same number (but not by zero)
Divide both sides by the same number (but not by zero)
(There are others, too, but they are not needed in simple equations.)
The goal is to FIRST add and subtract until we have ONLY x's (blocks) on one side and ONLY ones (circles) on the other. Then, if you have more than one block, you need to divide so as to arrive to the situation with only one block on the one side, which is the solved equation!
Answer:
that's good12 pages=1hour 6 pages= 30 min
A(t)=A0*(1/2)^(t/30)
where t=elapsed years
A0=initial mass at t=0.
From the cars parked in the lot he will earn (40)($10)=$400, but he will need to pay $50 for the rent. Thus his total $ earned will be $400-$50=$350.
