When a patient on antihypertensive therapy presents with tachycardia, the most important next assessment is to measure blood pressure. Blood pressure provides the direct hemodynamic status you need to guide management: if the reading is elevated, tachycardia may reflect uncontrolled hypertension or a compensatory response to stress, while a low reading could indicate overmedication, dehydration, or volume depletion. Knowing the exact systolic and diastolic values (and potentially performing orthostatic measurements) helps you decide whether to adjust antihyensive therapy, investigate for dehydration or ischemia, or address other causes of tachycardia. Other assessments have value in broader care but don’t directly inform how to manage the tachycardia in this context. Palpating pedal pulses assesses peripheral perfusion rather than systemic pressure. Counting the brachial pulse rate repeats the heart rate but misses the critical blood pressure status. Assessing for a carotid bruit screens for vascular disease rather than guiding acute antihypertensive management.

The main idea being assessed is the author's purpose. Because the paragraph argues that improving sleep leads to better memory, the writer is aiming to persuade readers to accept that claim and likely to act on it. It’s not just presenting information about sleep or memory, nor simply describing routines or providing entertainment; it’s urging a specific belief and action—that better sleep can enhance memory. That’s why this choice is the best: it captures the intent to convince readers to change or consider changing their sleep habits to improve memory. The other options would fit if the piece were mainly to entertain, to give a neutral overview of sleep science, or to describe routines without pushing readers to adopt a viewpoint or action.

Monitoring for Battle’s sign every four hours focuses on detecting a basilar skull fracture, a serious complication that can accompany hemorrhagic events. Battle’s sign is bruising behind the ear that suggests fracture at the base of the skull. If this fracture is present, there is a risk of CSF leakage, cranial nerve injury, and additional intracranial complications. Regular assessment allows for early intervention—prompt neuro checks, imaging as ordered, and precautions to protect airway and prevent infection. It also guides the team in avoiding nasal suctioning or nasal instrumentation if a fracture is suspected, and in monitoring for changes that could indicate worsening bleeding or new deficits. While maintaining ROM and avoiding Valsalva maneuvers are important components of stroke care, they do not directly address the immediate safety concern signaled by a basilar skull fracture. Keeping the head of the bed flat would actually raise intracranial pressure and is not appropriate in hemorrhagic stroke care.

Adding fractions with different denominators requires rewriting each fraction so they share a common denominator, then adding the numerators. For 3/4 and 5/6, a convenient common denominator is 12. Convert: 3/4 becomes 9/12 (multiply top and bottom by 3), and 5/6 becomes 10/12 (multiply top and bottom by 2). Now add: 9 + 10 = 19, giving 19/12. This improper fraction is equivalent to 1 7/12 if you prefer a mixed number. The other options don’t come from correct conversion to a common denominator and addition.