document.write( "Question 16536: if (a+2)x^2- 2ax - a = 0
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document.write( "what is range of a ? \n" );
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Algebra.Com's Answer #8082 by AnlytcPhil(1810) You can put this solution on YOUR website! \n" ); document.write( "if (a+2)x^2- 2ax - a = 0 \n" ); document.write( "` \n" ); document.write( "what is range of a ? \n" ); document.write( "` \n" ); document.write( "If you were to solve this problem by the quadratic formula, \n" ); document.write( "` \n" ); document.write( "A = (a+2), B = -2a, C = -a \n" ); document.write( "` \n" ); document.write( "the expression underneath the square root, B2 - 4AC, known as the \n" ); document.write( "'discriminant', must not be negative. \n" ); document.write( "` \n" ); document.write( "` ` ` ` ` `B2 - 4AC >= 0 \n" ); document.write( "` \n" ); document.write( "(-2a)2 - 4(a+2)(-a) >= 0 \n" ); document.write( "` \n" ); document.write( "` ` ` 4a2 + 4a(a+2) >= 0 \n" ); document.write( "` \n" ); document.write( "` ` `4a2 + 4a2 + 8a >= 0 \n" ); document.write( "` \n" ); document.write( "` ` ` ` ` `8a2 + 8a >= 0 \n" ); document.write( "` \n" ); document.write( "` ` ` ` ` 8a(a + 1) >= 0 \n" ); document.write( "` \n" ); document.write( "The zeros of the left side are 0 and -1 \n" ); document.write( "` \n" ); document.write( "Make a number line, and mark these solid since they are solutions. \n" ); document.write( "` \n" ); document.write( "----------•--•------------ \n" ); document.write( "-4 -3 -2 -1 `0 +1 +2 +3 +4 \n" ); document.write( "` \n" ); document.write( "Choose any value in the leftmost region, the region left of -1. The easiest \n" ); document.write( "value to choose is -2. Substitute it into the expression \n" ); document.write( "` \n" ); document.write( "8a(a + 1) \n" ); document.write( "8(-2)(-2 + 1) = -16(-1) = +16. This is nonnegative, so shade all those values. \n" ); document.write( "` \n" ); document.write( "<==========•--•------------ \n" ); document.write( "`-4 -3 -2 -1 0 +1 +2 +3 +4 \n" ); document.write( "` \n" ); document.write( "Choose any value in the middle region, the region between -1 and 0. The \n" ); document.write( "easiest value to choose is -1/2. Substitute it into the expression \n" ); document.write( "` \n" ); document.write( "8a(a + 1) \n" ); document.write( "8(-1/2)(-1/2 + 1) = -4(1/2) = -2. This is negative, so do not shade the values \n" ); document.write( "in the middle region. \n" ); document.write( "` \n" ); document.write( "Choose any value in the rightmost region, the region right of 0. The easiest \n" ); document.write( "value to choose is 1. Substitute it into the expression \n" ); document.write( "` \n" ); document.write( "8a(a + 1) \n" ); document.write( "8(1)(1 + 1) = 8(2) = +16. This is nonnegative, so shade all those values. \n" ); document.write( "` \n" ); document.write( "<==========•--•============> \n" ); document.write( "`-4 -3 -2 -1 `0 +1 +2 +3 +4 \n" ); document.write( "` \n" ); document.write( "The interval notation for this is \n" ); document.write( "` \n" ); document.write( "(-¥,-1] U [0, ¥) \n" ); document.write( "` \n" ); document.write( "Edwin \n" ); document.write( "AnlytcPhil@aol.com \n" ); document.write( " |