How many real solutions exist for the equation x2– 11|x| - 60 = ...
Step 1: Assign y = |x| and solve for y
Let |x| = y.
We can rewrite the equation x2 - 11|x| - 60 = 0 as y2 - 11y - 60 = 0
The equation can be factorized as y2 - 15y + 4y - 60 = 0
(y - 15) (y + 4) = 0
The values of y that satisfy the equation are y = 15 or y = -4.
Step 2: Compute number of real values of x
We have assigned y = |x|
|x| is always a non-negative number.
So, |x| cannot be -4.
|x| can take only one value = 15.
If |x| = 15, x = 15 or -15.
The number of real solutions that exist for x2 – 11|x| - 60 = 0 is 2.
The correct choice is (B) and the correct answer is 2.
View all questions of this test
How many real solutions exist for the equation x2– 11|x| - 60 = ...
Analysis:
To find the number of real solutions for the given equation x^2 - 11|x| - 60 = 0, we need to consider two cases: when x is positive and when x is negative.
Case 1: x is positive
When x is positive, the equation becomes x^2 - 11x - 60 = 0.
Factoring the equation, we get (x - 15)(x + 4) = 0.
This gives us two possible solutions: x = 15 and x = -4.
Case 2: x is negative
When x is negative, the equation becomes x^2 + 11x - 60 = 0.
Factoring the equation, we get (x + 15)(x - 4) = 0.
This gives us two possible solutions: x = -15 and x = 4.
Combining the solutions:
Since we are looking for real solutions, we can see that only x = 4 is a valid solution that satisfies the absolute value requirement. Therefore, there are 2 real solutions for the equation x^2 - 11|x| - 60 = 0.
Therefore, the correct answer is option B) 2.