Question Details

Directions: Solve the two equations given below and choose the correct relationship between x and y.

I. ( x 3 ) 2 = 64

II. 2 y 2 + 15y + 28 = 0

Options

A

If x < y

B

If x > y

C

If x = y or no relation can be established between x and y

D

If x ≥ y

E

If x ≤ y

Show Answer

Correct Answer :

Option C

If x = y or no relation can be established between x and y

Solution :

The correct option is If x = y or no relation can be established between x and y.

To find the relationship between x and y, we need to solve both given equations to find their respective roots and then compare all possible values of x and y.

Step 1: Solve Equation I for x

The first equation is given as:

( x - 3 ) 2 = 64

Taking the square root on both sides gives:

x - 3 = ± 8

This gives two possible equations for x:

x - 3 = 8 x = 8 + 3 = 11

OR

x - 3 = - 8 x = - 8 + 3 = - 5

Thus, the values of x are 11 and -5.

Step 2: Solve Equation II for y

The second quadratic equation is given as:

2 y 2 + 15 y + 28 = 0

We solve this by splitting the middle term. We need two factors whose product is 2 × 28 = 56 and whose sum is 15. The numbers 8 and 7 satisfy this condition (8 × 7 = 56 and 8 + 7 = 15):

2 y 2 + 8 y + 7 y + 28 = 0

Factor out common terms:

2 y ( y + 4 ) + 7 ( y+ 4 ) = 0

( 2 y + 7 ) ( y + 4 ) = 0

Equating each factor to zero:

2 y + 7 = 0 y = - 7 2 = - 3.5

OR

y + 4 = 0 y = - 4

Thus, the values of y are -3.5 and -4.

Step 3: Compare the values of x and y

Let us compare each value of x with each value of y:

1. When x = 11 and y = -3.5: 11 > -3.5, so x > y.
2. When x = 11 and y = -4: 11 > -4, so x > y.
3. When x = -5 and y = -3.5: -5 < -3.5, so x < y.
4. When x = -5 and y = -4: -5 < -4, so x < y.

Since x can be both greater than y and less than y depending on the roots considered, no fixed relationship can be established between x and y.

Hence, the correct choice is If x = y or no relation can be established between x and y.

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