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If x = 3 is solution of x² + kx + 15, value of k is
- a)k = -8, x = 3
- b)k = 8, x = 5
- c)k = 6, x = 5
- d)None of above
Correct answer is option 'A'. Can you explain this answer?
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If x = 3 is solution of x² + kx + 15, value of k isa)k = -8, x = 3b)k ...
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If x = 3 is solution of x² + kx + 15, value of k isa)k = -8, x = 3b)k ...
Understanding the Problem
We need to find the value of k in the equation x² + kx + 15, given that x = 3 is a solution.
Step 1: Substitute x = 3
To find k, we will substitute x = 3 into the equation:
- Replace x in the equation:
(3)² + k(3) + 15 = 0
- Calculate (3)²:
9 + 3k + 15 = 0
Step 2: Simplify the Equation
Combine the constant terms:
- 9 + 15 = 24
Thus, we have:
3k + 24 = 0
Step 3: Solve for k
Now, isolate k:
- 3k = -24
- k = -24 / 3
- k = -8
Conclusion
The value of k that makes x = 3 a solution of the equation x² + kx + 15 is k = -8.
Thus, the correct answer is option A: k = -8, x = 3.
We need to find the value of k in the equation x² + kx + 15, given that x = 3 is a solution.
Step 1: Substitute x = 3
To find k, we will substitute x = 3 into the equation:
- Replace x in the equation:
(3)² + k(3) + 15 = 0
- Calculate (3)²:
9 + 3k + 15 = 0
Step 2: Simplify the Equation
Combine the constant terms:
- 9 + 15 = 24
Thus, we have:
3k + 24 = 0
Step 3: Solve for k
Now, isolate k:
- 3k = -24
- k = -24 / 3
- k = -8
Conclusion
The value of k that makes x = 3 a solution of the equation x² + kx + 15 is k = -8.
Thus, the correct answer is option A: k = -8, x = 3.
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