Question

One of the roots of quadratic equation 2x²+kx-3=0 is -3. Find k?​

Answer 1

Given:-

• One of root is -3 means x = -3

To find :- value of k

SolutioN:-

• Put the value of x in equation

=> 2x²+kx-3=0

=> 2 × ( -3)² + k (-3) -3 = 0

=> 81 - 3 k -3 = 0

=> 81 - 3 + 3 k = 0

=> 78 + 3k = 0

=> 3 k = -78

=> k = -78/3

=> k = -26

Verification:-

=> 2x²+kx-3=0

• Put the value of x = -3 and k = -25 in equation.

=> 2 × ( -3)² + (-26) × (-3) -3 = 0

=> 81 - 78 -3 = 0

=> 81 - 81 =0

=> 0= 0

Hence the value of k is -26

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More information:-

• This is type of quadratic equation means this equation has 2 roots or we can say 2 zeros or factors.
• Quadratic equation always have degree 2.

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