document.write( "Question 366422: write the eqution of the line that passes throgh (1,-1)and(-2,5) \n" ); document.write( "
Algebra.Com's Answer #261157 by Jk22(389)\"\" \"About 
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Points : (1,-1) and (-2,5)
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\n" ); document.write( "Equation of a line : y = ax + b
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\n" ); document.write( "equations obtained :
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\n" ); document.write( "-1 = a + b
\n" ); document.write( "5 = -2a + b
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\n" ); document.write( "subtracting equation 1 from equation 2 : -3a = 6 => a = -2
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\n" ); document.write( "b = -1 - a = 1
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\n" ); document.write( "thus y = -2x + 1, or y + 2x = 1
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\n" ); document.write( "Verification : -1 + 2 = 1, and 5 - 4 = 1\r
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