Question -
Answer -
Given: 9x2 +4 = 0
9x2 +4 × 1 = 0
We know, i2 =–1 ⇒ 1 = –i2
By substituting 1 = –i2 inthe above equation, we get
So,
9x2 +4(–i2) = 0
9x2 –4i2 = 0
(3x)2 –(2i)2 = 0
[Byusing the formula, a2 – b2 = (a + b) (a –b)]
(3x + 2i) (3x – 2i) =0
3x + 2i = 0 or 3x – 2i= 0
3x = –2i or 3x = 2i
x = -2i/3 or x = 2i/3
∴ The roots of thegiven equation are 2i/3, -2i/3