document.write( "Question 1040428: Hi there, I'm confused on the following problem and could use some help please:\r
\n" ); document.write( "\n" ); document.write( "I need to multiply and simplify (5 + 7i)^2. Am I going to multiply 5 x 5 then 7i x 7i?\r
\n" ); document.write( "\n" ); document.write( "I would really appreciate some help, thank you! \n" ); document.write( "

Algebra.Com's Answer #655233 by ikleyn(52906) $\"\"$ $\"About$

You can put this solution on YOUR website!
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\n" ); document.write( "I need to multiply and simplify (5 + 7i)^2. Am I going to multiply 5 x 5 then 7i x 7i?\r
\n" ); document.write( "\n" ); document.write( "I would really appreciate some help, thank you!
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document.write( "1.  What you are planning to do is incorrect.\r\n" );
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document.write( "2.  Do you know this formula:  =  ?\r\n" );
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document.write( "    It is applicable to complex numbers exactly as it is applicable to real numbers.\r\n" );
document.write( "    (It is a general formula !)\r\n" );
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document.write( "3.  So, you need to take ,  and  and add up these addends. You will get\r\n" );
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document.write( "    .\r\n" );
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document.write( "    Now, you should remember that  = . So your sum is\r\n" );
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document.write( "    25 + 70i -49 = -24 + 70i.\r\n" );
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document.write( "It is your answer.\r\n" );
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document.write( "Answer.   = -24 + 70i.\r\n" );
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\n" ); document.write( "\n" ); document.write( "On complex numbers see the lessons\r
\n" ); document.write( "\n" ); document.write( "    - Complex numbers and arithmetic operations on them\r
\n" ); document.write( "\n" ); document.write( "    - Complex plane\r
\n" ); document.write( "\n" ); document.write( "    - Addition and subtraction of complex numbers in complex plane\r
\n" ); document.write( "\n" ); document.write( "    - Multiplication and division of complex numbers in complex plane\r
\n" ); document.write( "\n" ); document.write( "    - Raising a complex number to an integer power\r
\n" ); document.write( "\n" ); document.write( "    - How to take a root of a complex number\r
\n" ); document.write( "\n" ); document.write( "    - Solution of the quadratic equation with real coefficients on complex domain\r
\n" ); document.write( "\n" ); document.write( "    - How to take a square root of a complex number\r
\n" ); document.write( "\n" ); document.write( "    - Solution of the quadratic equation with complex coefficients on complex domain\r
\n" ); document.write( "\n" ); document.write( "in this site.\r
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\n" ); document.write( "\n" ); document.write( "It is your online mini-textbook on complex numbers.\r
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