Difficulty: Medium
Correct Answer: (12/13, 18/13)
Explanation:
Introduction / Context:
This question involves basic analytic geometry: slopes of lines, perpendicularity, and intersection points. Many competitive exams use such problems to test your ability to convert between different forms of line equations and to apply algebraic methods to find coordinates of intersection points.
Given Data / Assumptions:
Concept / Approach:
First, find the slope of the given line by rewriting it in slope intercept form y = mx + c. A line perpendicular to a given line has a slope equal to the negative reciprocal of the original slope. Once we know the slope of the perpendicular line and the fact that it passes through the origin, we can write its equation. Finally, we solve the system of two linear equations in two variables to find the intersection point M.
Step-by-Step Solution:
Rewrite 2x + 3y = 6 as y = (-2/3)x + 2, so the slope of this line is -2/3.The slope of any line perpendicular to this is the negative reciprocal, which is 3/2.Since the perpendicular line passes through the origin, its equation is y = (3/2)x.To find M, solve 2x + 3y = 6 together with y = (3/2)x. Substitute y into the first equation: 2x + 3 * (3/2)x = 6.This gives 2x + 9x/2 = 6, so (4x + 9x) / 2 = 6, which simplifies to 13x / 2 = 6 and then x = 12/13. Substituting back into y = (3/2)x gives y = (3/2) * 12/13 = 18/13. So M is (12/13, 18/13).
Verification / Alternative check:
We can verify by showing that M satisfies both equations. For 2x + 3y = 6, substitute x = 12/13, y = 18/13: 2 * 12/13 + 3 * 18/13 = 24/13 + 54/13 = 78/13 = 6, which is correct. For y = (3/2)x, we have (3/2) * 12/13 = 36/26 = 18/13, which matches y. Also, the product of slopes of the two lines is (-2/3) * (3/2) = -1, confirming perpendicularity.
Why Other Options Are Wrong:
Common Pitfalls:
Final Answer:
(12/13, 18/13)
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