Question

If one root of the quadratic equation x square -11x+k=0 is 9 find the value of k

Answer 1

putting value of x =9
81 - 11× 9 + k=0
81 - 99 + k=0
k= 18

Answer 2

Answer:

Step-by-step explanation:

let the other root be y

therefore two roots will be 9 and y

as the roots sum should be equal to - b/a

therefore 9 + y= -(-11)/1

therefore y = 2

and also the product of roots is equal to c/a

therefore (9)(2) = k/1

therefore k = 18