Correct Answer - Option 5 : No relation in x and y or x = y
Given:
I. x2 - 6x - 40 = 0
II. y2 - 7y + 12 = 0
Calculation:
From I
x2 - 6x - 40 = 0
⇒ x2 - 10x + 4x - 40 = 0
⇒ x(x - 10) + 4(x - 10) = 0
⇒ (x - 10)(x + 4) = 0
⇒ x = 10, -4
From II
y2 - 7y + 12 = 0
⇒ y2 - 3y - 4y + 12 = 0
⇒ y(y - 3) - 4(y - 3) = 0
⇒ (y - 3)(y - 4) = 0
⇒ y = 3, 4
Comparison between x and y (via Tabulation)
Value of x |
Value of y |
Relation between x & y |
10 |
3 |
x > y |
10 |
4 |
x > y |
-4 |
3 |
x < y |
-4 |
4 |
x < y |
∴ No relation in x and y or x = y
Sign Method
|
Equation
|
Sign
|
Remark
|
ax2 + bx + c = 0
|
-Ve, -Ve
|
Same signs
|
ax2 - bx + c = 0
|
+Ve, +Ve
|
Same signs
|
ax2 + bx - c = 0
|
-Ve, +Ve
|
Larger root is negative
smaller root is positive
|
ax2 - bx - c = 0
|
-Ve, +Ve
|
Larger root is positive
smaller root is negative
|