Question

if a is a root of the equation x2 -(a+b)x + K = 0 find the value of k

Answer 1

@=a
x2-(a+b)x + k=0
put x=a in above equation
a2-(a+b)a+k=0
a2-(a2+ab) +k=0
a2-a2-ab+k=0
-ab+k=0
k=ab