Question

If one zero of the quadratic polynomial x2+x-2 is -2 then find other zeroes

Answer 1

If α and β are zeroes of quadratic polynomial than the quadratic polynomial is given by k ( x² - ( α + β ) x + αβ ) , where ( α + β ) is sum of zeroes and αβ is product of zeroes.

x² + 2x - 2

⇒ α + β = -1

⇒ αβ = -2

Since we know one of the zero is -2,

⇒ let α = -2

FInd β:

-2 + β = -1

β = - 1 + 2

β = 1

To check:

αβ = -2

(-2)β = -2

β = -2 ÷ (-2)

β = 1

Answer: The other zero is 1.