Set 7: Linear Functions (Intermediate)

Explanation

Answer: A

Write the equation of a line perpendicular to $y = 3x$ passing through the origin.

$y = -\frac{1}{3}x$

✓ Correct

$y = 3x$

$y = \frac{1}{3}x$

$y = -3x$

Detailed Explanation

Choice A is correct. Choice A is the correct answer. Negative reciprocal slope. 1. Original Slope: $3$ . 2. New Slope: $-1/3$ . 3. Intercept: Origin $\rightarrow b=0$ . 4. Equation: $y = -\frac{1}{3}x$ . Strategic Tip: Perpendicular to steep uphill is shallow downhill. Choice B is incorrect because parallel. Choice C is incorrect because sign error. Choice D is incorrect because reciprocal error.

Key Steps:

•

The correct answer is $y = -\frac{1}{3}x$

Why others are wrong:

B: Choice B is incorrect and may result from a calculation error.

C: Choice C is incorrect and may result from a calculation error.

D: Choice D is incorrect and may result from a calculation error.

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