Difficulty: Easy
Correct Answer: y = 4x
Explanation:
Introduction / Context:This concept check asks you to match a verbal line description to its algebraic form. “Ordinate” means y-coordinate and “abscissa” means x-coordinate. Saying “the ordinate is four times the abscissa” translates directly to y = 4x for every point on the line.
Given Data / Assumptions:
Concept / Approach:Translate words to symbols. “y is four times x” → y = 4x. Check each option by rearranging to an explicit y = mx form where possible, and compare the slope and proportionality to 4.
Step-by-Step Solution:
Target relation: y = 4x Option A: y + 4x = 0 ⇒ y = −4x (wrong sign). Option B: y = 4x (exact match). Option C: x = 4y ⇒ y = x/4 (reciprocal slope). Option D: x + 4y = 0 ⇒ y = −x/4 (negative reciprocal). Option E: y = −4x (negative slope).Verification / Alternative check:Pick x = 2. Then y must be 8. Only y = 4x passes the test exactly for all x.
Why Other Options Are Wrong:They represent lines with slopes −4, 1/4, or −1/4, none of which encode y being four times x.
Common Pitfalls:Confusing “four times” (multiply by 4) with “one fourth” (divide by 4), or missing the negative sign when moving terms across the equals sign.
Final Answer:y = 4x
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