document.write( "Question 717520: when solving -x2+2x+1=y when x is -1, would it be -1 + -2 +1= y or 1 + -2 + 1=y? \n" ); document.write( "
Algebra.Com's Answer #440331 by jsmallt9(3758)\"\" \"About 
You can put this solution on YOUR website!
Your question, in simpler terms, is: What is \"-x%5E2\" when x = -1?

\n" ); document.write( "The answer requires that we understand a fundamental fact about exponents: Exponents apply only to what is immediately in front of them. (\"Immediately in front\" means literally \"the very first character to the left of\"
  • If a digit (0-9) is immediately in front of the exponent, the exponent applies only to the number which that digit is the last/only digit. Important: If there is a \"-\" in front of this number, the exponent does not apply to it! For example:
    \n" ); document.write( "\"-10%5E2\" means -(10*10) which equals -100 (not (-10)(-10) which equals 100.
  • If a variable is immediately in front of an exponent, the exponent applies only to that variable, not to any other variables or numbers which may precede that variable. For example, \"24xy%5E3\" means 24*x*y*y*y.
  • If a end-of-a-group symbol (like \"}\" or \"]\" or \"}\") is immediately in front of an exponent, it applies to the entire grouped expression. For example, \"%28x%5E2-4x%2B3%29%5E3\" means \"%28x%5E2-4x%2B3%29%2A%28x%5E2-4x%2B3%29%2A%28x%5E2-4x%2B3%29\" but \"x%5E2-4x%2B3%5E3\" means just \"x%5E2-4x%2B3%2A3%2A3\"
The way exponents work like this is another reason it is a good idea to use parentheses when making substitutions. If you substitute a -1 into \"x%5E2\" with parentheses you get:
\n" ); document.write( "\"%28-1%29%5E2+=+%28-1%29%2A%28-1%29+=+1\"
\n" ); document.write( "Without the parentheses we would have:
\n" ); document.write( "\"-1%5E2+=+-1%2A1+=+-1\"

\n" ); document.write( "Finally we'll answer your question, if you haven't figured it out already. \"-x%5E2\" when x = -1:
\n" ); document.write( "\"-%28-1%29%5E2+=+-%28-1%29%2A%28-1%29+=+-1\" \n" ); document.write( "
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