document.write( "Question 1170561: Solve for x: x^2+16=0 (complex numbers) \n" ); document.write( "
Algebra.Com's Answer #795414 by Theo(13342)\"\" \"About 
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equation is x^2 + 16 = 0
\n" ); document.write( "subtract 16 from both sides of the equqtion to get:
\n" ); document.write( "x^2 = -16
\n" ); document.write( "solve for x to get:|
\n" ); document.write( "x = plus or minus sqrt(-16)
\n" ); document.write( "sqrt(-16) = sqrt(16*-1) = 4*sqrt(-1) = = 4i
\n" ); document.write( "x = plus or minus 4i.\r
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\n" ); document.write( "\n" ); document.write( "that should be your answer.
\n" ); document.write( "to confirm, replace x with plus or minus 4i in the original equation to get:\r
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\n" ); document.write( "\n" ); document.write( "when x = 4i,the equation becomes (4i)^2 + 16 = 0.
\n" ); document.write( "(4i)^2 becomes 4^2 * i^2 = 16 * -1 = -16.
\n" ); document.write( "equation becomes -16 + 16 = 0, which is true, confirming x = 4i is a solution.\r
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\n" ); document.write( "\n" ); document.write( "when x = -4i, the equation becomes (-4i)^2 + 16 = 0
\n" ); document.write( "(-4i)^2 becomes (-1)^2 * 4^2 * i^2 = 1 * 16 * -1 = -16.
\n" ); document.write( "equation becomes -16 + 16 = 0, which is true, confirming x = -4i is also a solution.\r
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\n" ); document.write( "\n" ); document.write( "the solution is x = plus or minus 4i.\r
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