Find the Zeros of f(x) = 6x² − 7x − 3 and Verify the Relationship Between Zeros and Coefficients
Video Explanation
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Solution
Given polynomial:
f(x) = 6x² − 3 − 7x
Rearranging in standard form:
f(x) = 6x² − 7x − 3
Step 1: Find the Zeros of the Polynomial
6x² − 7x − 3 = 0
Split the middle term:
6x² − 9x + 2x − 3 = 0
Grouping the terms:
3x(2x − 3) + 1(2x − 3) = 0
(3x + 1)(2x − 3) = 0
∴ 3x + 1 = 0 or 2x − 3 = 0
∴ x = −1/3 or x = 3/2
Zeros of the polynomial are −1/3 and 3/2.
Step 2: Identify Coefficients
Comparing f(x) = 6x² − 7x − 3 with ax² + bx + c:
a = 6, b = −7, c = −3
Step 3: Verify the Relationship
Let α = 3/2 and β = −1/3
Sum of zeros:
α + β = 3/2 + (−1/3)
= (9 − 2)/6 = 7/6
−b/a = −(−7)/6 = 7/6
✔ Sum of zeros = −b/a
Product of zeros:
αβ = (3/2)(−1/3) = −1/2
c/a = −3/6 = −1/2
✔ Product of zeros = c/a
Final Answer
Zeros of the polynomial are 3/2 and −1/3.
The relationship between zeros and coefficients is verified.
Conclusion
Thus, for the quadratic polynomial f(x) = 6x² − 7x − 3, the sum and product of zeros satisfy the standard relationships with its coefficients.