Difficulty: Medium
Correct Answer: 3x + 5y = 12
Explanation:
Introduction / Context:
This problem combines concepts of intercepts and the general equation of a straight line. You are given one point through which the line passes and the x-intercept. From this information you must determine the line equation that satisfies both conditions. Such questions are standard in coordinate geometry sections of aptitude tests.
Given Data / Assumptions:
Concept / Approach:
A line is uniquely determined by two distinct points. We first compute the slope using the two points, then use the point slope form of the line equation and transform it into a standard linear form. Finally, we compare this equation with the options provided. Alternatively, we can derive the equation directly in intercept form and verify with one point.
Step-by-Step Solution:
Let the two points be P(-1, 3) and Q(4, 0).Compute the slope m: m = (y2 − y1) / (x2 − x1) = (0 − 3) / (4 − (-1)) = -3 / 5.Use the point slope form with point Q(4, 0): y − 0 = m(x − 4) so y = (-3/5)(x − 4).Expand: y = (-3/5)x + (12/5).Multiply both sides by 5 to remove the denominator: 5y = -3x + 12, or rearranged as 3x + 5y = 12.
Verification / Alternative check:
Check that both given points satisfy the equation 3x + 5y = 12. For (4, 0), we have 3 * 4 + 5 * 0 = 12, which is correct. For (-1, 3), we have 3 * (-1) + 5 * 3 = -3 + 15 = 12, which also works. Therefore, 3x + 5y = 12 is the correct line. None of the other options satisfy both points simultaneously.
Why Other Options Are Wrong:
Common Pitfalls:
Final Answer:
3x + 5y = 12
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