# Solve the following quadratic equations by factorization method9x2 + 4 = 0

Given 9x2 + 4 = 0

9x2 + 4 × 1 = 0

We have i2 = –1 1 = –i2

By substituting 1 = –i2 in the above equation, we get

9x2 + 4(–i2) = 0

9x2 – 4i2 = 0

(3x)2 – (2i)2 = 0

(3x + 2i)(3x – 2i) = 0 [ a2 – b2 = (a + b)(a – b)]

3x + 2i = 0 or 3x – 2i = 0

3x = –2i or 3x = 2i  Thus, the roots of the given equation are .

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