Question

If one root of the quadratic, x² - 7x + k = 0 is 4. then find the value of k.

Answer 1

x² - 7x + k = 0 ( Given )

∵ 4 is the root of this quadratic equation. 

∴ 4 will satisfy this equation. 

∴ Put x = a 

 4² - 7( 4) + k = 0

∴ 16 - 28 + k = 0

         -12 + k = 0

              ∴ k  = 12