One of the roots of the equation x² - 13x + k = 0 is x = 4. The other root is:

Question: One of the roots of the equation x² - 13x + k = 0 is x = 4. The other root is:

Solution:
Let us put x = 4 in the equation x² - 13x + k = 0,
⇒ 16 - 52 + k = 0
⇒ k = 36

Putting the value of k in the equation,
we get:
x² - 13x + 36 = 0
⇒ x² - 9x - 4x + 36 = 0
⇒ x(x - 9) - 4 (x - 9) = 0
⇒ (x - 4)(x - 9) = 0
⇒ x = 4 and 9

∴ Other root of the equation is 9