Question

Apabila persamaan x^2 + mx + 1 = 0 dan x^2 + x + m = 0 mempunyai 1 akar perserikatan, hitunglah m dan akar-akar itu!

Answer 1

X² +mx + 1 = x² + x + m
mx+ 1 = x + m
mx - x = m - 1
x(m-1) = (m-1)
x  = 1 sub ke x² + mx +1 =0
1 + m +1 = 0
m = -2
..
m = - 2 , dan akarnya x= 1

Answer 2

X^2 + mx + 1 = x^2 + x + m
x^2 - x^2 +mx -x +1 -m = 0
x(m -1) + (1 -m) = 0
syarat punya satu akar perserikatan D =0
b² -4ac = 0
(m-1)² - (4.0.(1-m)) = 0
(m-1)² =0
m = 1