In each of these questions, two equation (I) and (II) are given. You have to…
2023
In each of these questions, two equation (I) and (II) are given. You have to solve both the equations and give answer.
I. 3x² - 37x + 114 = 0
II. 3y² - 46y + 171 = 0
- A.
If x > y
- B.
If x ≥ y
- C.
If x < y
- D.
If x ≤ y
- E.
If x = y or no relation can be established between x and y
Attempted by 3 students.
Show answer & explanation
Correct answer: D
Concept: To compare the roots of two quadratics, factor each into the form (px − a)(qx − b) = 0 to read off its roots, list both root sets, then compare them pairwise. A single inequality (≤, <, >, ≥) holds only if it is true for every pairing of an x-root with a y-root; equality at any boundary forces the relation to use ≤ or ≥ rather than the strict form.
Application — solve Equation I (3x2 − 37x + 114 = 0):
Factor: 3x2 − 37x + 114 = (3x − 19)(x − 6) = 0.
Set each factor to zero: 3x − 19 = 0 gives x = 19/3 ≈ 6.33; x − 6 = 0 gives x = 6.
So the x-roots are 6 and 19/3 (≈ 6.33).
Application — solve Equation II (3y2 − 46y + 171 = 0):
Factor: 3y2 − 46y + 171 = (3y − 19)(y − 9) = 0.
Set each factor to zero: 3y − 19 = 0 gives y = 19/3 ≈ 6.33; y − 9 = 0 gives y = 9.
So the y-roots are 19/3 (≈ 6.33) and 9.
Compare the root sets pairwise:
Smallest x = 6 against y = 19/3 and y = 9: 6 < 6.33 and 6 < 9, so x < y here.
Largest x = 19/3 against y = 19/3: 6.33 = 6.33, so x = y at this boundary.
Largest x = 19/3 against y = 9: 6.33 < 9, so x < y here.
In every pairing x is less than y, except at one boundary where x = y. No pairing makes x larger than y. Because equality occurs at the boundary, the strict relation x < y cannot be claimed for all cases; the correct, fully-true relation is x ≤ y.
Cross-check: the maximum x-value (19/3) equals the minimum y-value (19/3), and the minimum x-value (6) is below it — so the entire x-set lies at or below the entire y-set, confirming x ≤ y.