Solve the following quadratic equations:


Given


Recall that the roots of quadratic equation ax2 + bx + c = 0, where a ≠ 0, are given by



Here, a = 2, and c = –i




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





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




We can write 15 – 8i = 16 – 1 – 8i


15 – 8i = 16 + (–1) – 8i


15 – 8i = 16 + i2 – 8i [ i2 = –1]


15 – 8i = 42 + (i)2 – 2(4)(i)


15 – 8i = (4 – i)2 [ (a – b)2 = a2 – b2 + 2ab]


By using the result 15 – 8i = (4 – i)2, we get






[ i2 = –1]





Thus, the roots of the given equation are and.


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