Option A ($1,620 credit) is correct.

Only one-sided errors affect the suspense account:

• Error 1 (complete omission): Does NOT affect suspense.
• Error 2: Purchases understated by $1,980 → Debit Purchases, Credit Suspense $1,980.
• Error 3: Rent overposted by $3,600 → Debit Suspense, Credit Rent $3,600.

Net: Dr $3,600 − Cr $1,980 = Dr $1,620 needed → original balance was $1,620 credit.

Subtract equation 1 from equation 2: $(a-1)y = 0$.

Case $a\neq1$: $y=0$. Then from eq.1 and eq.3: $x+z=1$ and $ax+z=0$, giving $(a-1)x=-1$, so $x=\frac{-1}{a-1}$. This always has a solution for $a\neq1$.

Case $a=1$: System becomes $x+y+z=1$, $x+y+z=1$, $x+by+z=0$. The third equation forces $-1=by-... $ i.e. subtracting eq.1: $(b-1)y=-1$. For no solution we need $b=1$.

So $S=\{1\}$ — a single value. Hence $S$ is a singleton.

1. Hypertension (widened pulse pressure) — body attempts to perfuse brain against rising ICP
2. Bradycardia — reflex response (baroreceptor) to hypertension
3. Irregular respirations — Cheyne-Stokes or ataxic breathing due to brainstem compression

• Immediately notify the neurosurgeon and intensivist
• Elevate HOB to \(30°\)
• Administer Mannitol \(0.25 - 1 \text{ g/kg}\) IV or 3% NaCl
• Prepare for emergency ICP monitoring or surgical decompression
• Avoid hypotension (maintain CPP \(\geq 60 \text{ mmHg}\))
• Avoid hyperthermia and hypoxia

Management has become increasingly complex and demanding for all four reasons: foreign competition, new technology, expanding scientific information, and rapid change. This complexity leads organizations to ask HR managers for assistance in strategic decisions.