Question

In each of the following find the values of k of which the given value is a solution of the given equation:
x² - x(a + b) + k = 0, x = a

Answer 1

x² - x(a + b) + k = 0, x = a.
Putting x = a in L.H.S. of equation
⇒ (a)² - a(a + b) + k = 0
⇒ a² - a² - ab + k = 0
Hence, k = ab.