Question

if both the zeros of a quadratic polynomelial x square +mx+9 are equal find the value of m​

Answer 1

Answer:

±6

Step-by-step explanation:

x square +mx+9 = 0

x ² + mx + 9 = 0

m² = 36

m = ±6

Answer 2

Answer:

±6

Step-by-step explanation:

Let α and β be the roots of quadratic polynomial.

Given, α = β

        Quadratic polynomial - x² + mx + 9

a = 1, b = m, c = 9.

Sum of roots, α + β =  -b/a = -m/1  ------------ [1]

product of roots, αβ = c/a  = 9 ----------- [2]

Since α = β, [2] becomes

α² = 9

=> α = ±3

Substitute the value of α in [1],

α + β = -m

2α = - m ( since α = β)

=> if α = + 3 then  m =  - 6

   if α = - 3, then m = + 6

Thus value of m is ±6