document.write( "Question 182245This question is from textbook algebra II
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\n" ); document.write( "x2 + 9x = -20 \n" ); document.write( "

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x²+ 9x = -20
\n" ); document.write( "First, add 20 on both the sides
\n" ); document.write( "x²+ 9x + 20 = -20 + 20
\n" ); document.write( "x²+ 9x + 20 = 0
\n" ); document.write( "Now split 9x as sum of 4x and 5x
\n" ); document.write( "x²+ 4x + 5x +20=0
\n" ); document.write( "Now, take x common from the first two terms.
\n" ); document.write( "And take 5 common from the next two terms.\r
\n" ); document.write( "\n" ); document.write( "x(x+4)+5(x+4)=0
\n" ); document.write( "(x+4)(x+5)=0
\n" ); document.write( "Using the zero-product rule
\n" ); document.write( "If the product of two numbers is 0, then either of the numbers is 0
\n" ); document.write( "so, (x+4)=0 or (x+5)=0
\n" ); document.write( "thus, x=-4 or x=-5
\n" ); document.write( "Ans: x=-4,-5 \r
\n" ); document.write( "\n" ); document.write( "Proof:
\n" ); document.write( "Put x=-4 in the equation
\n" ); document.write( "x²+ 9x= (-4)²+9(-4) = 16 - 36 = -20
\n" ); document.write( "now put x=-5 in the equation
\n" ); document.write( "x²+ 9x= (-5)²+9(-5) = 25 - 45 = -20
\n" ); document.write( "Thus, both the values are satisfied. \n" ); document.write( "

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