$726.34 + 888.12 - $ $x$ $= 1001.88$

### Concept & Formula When solving for a negative variable $-x$, shift it to the opposite side of the equation to make it positive, and bring the numeric total on the right back across the equation using subtraction. $$ a + b - x = c \implies x = a + b - c $$ ### Step-by-Step Solution * State the provided problem condition: * $726.34 + 888.12 - x = 1001.88$ * Solve for the isolated variable $x$: * $x = 726.34 + 888.12 - 1001.88$ * Add the two leading positive numbers: * $726.34 + 888.12 = 1614.46$ * Subtract the right-side constant value: * $x = 1614.46 - 1001.88$ * Calculate the subtraction carefully: * $1614.46 - 1001.88 = 612.58$ * Review options: (a) $602.64$, (b) $618.78$, (c) $621.58$, (d) $654.54$. Since $612.58$ is not listed, the choice falls to "None of these". ### Exam Strategy & Shortcut **Last Two Digits Valuation:** Analyze the terminal fractional parts: $.34 + .12 - .88 = .46 - .88 = -.42 \rightarrow 1.00 - 0.42 = .58$. The final value must end precisely in $.58$. Options matching this are limited to (c) $621.58$. Let's double check via fast estimation: $726 + 888 - 1001 \approx 1614 - 1001 = 613$. Option (c) is $621.58$, which is too high. Therefore, option (e) "None of these" is verified correct. ### Common Pitfall Misinterpreting a close alternative like $621.58$ as correct due to identical decimal suffixes without verifying the whole integer result is a classic trap layout. ### Final Answer **Therefore, the correct answer is None of these.**