Solve the following quadratic equations:
(2 + i)x2 – (5 – i)x + 2(1 – i) = 0
(2 + i)x2 – (5 – i)x + 2(1 – i) = 0
Given (2 + i)x2 – (5 – i)x + 2(1 – i) = 0
Recall that the roots of quadratic equation ax2 + bx + c = 0, where a ≠ 0, are given by
Here, a = (2 + i), b = –(5 – i) and c = 2(1 – i)
By substituting i2 = –1 in the above equation, we get
We can write –2i = –2i + 1 – 1
⇒ –2i = –2i + 1 + i2 [∵ i2 = –1]
⇒ –2i = 1 – 2i + i2
⇒ –2i = 12 – 2(1)(i) + i2
⇒ –2i = (1 – i)2 [∵ (a – b)2 = a2 – 2ab + b2]
By using the result –2i = (1 – i)2, we get
[∵ i2 = –1]
Thus, the roots of the given equation are 1 – i and.