document.write( "Question 208439: 20-4 over 5x is greater then or equal to 16?
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document.write( "greater then=> (if i have it wrong, its less then) \n" );
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Algebra.Com's Answer #157657 by Theo(13342)![]() ![]() You can put this solution on YOUR website! you manipulate inequalities much the same way you manipulate equalities. \n" ); document.write( "the only real difference is that if you multiply both sides of an inequality by -1 then you reverse the inequality. \n" ); document.write( "example: \n" ); document.write( "----- \n" ); document.write( "equality: \n" ); document.write( "a = b \n" ); document.write( "multiply both sides by -1 to get: \n" ); document.write( "-a = -b \n" ); document.write( "the signs are reversed and the equality is preserved. \n" ); document.write( "----- \n" ); document.write( "inequality: \n" ); document.write( "a > b \n" ); document.write( "multiply both sides by -1 to get: \n" ); document.write( "-a < -b \n" ); document.write( "the signs are reversed and the inequality is reversed. where it said > now it says <. \n" ); document.write( "----- \n" ); document.write( "your equation looks like this: \n" ); document.write( "(20-4)/5x >= 16 \n" ); document.write( "as far as i can tell. \n" ); document.write( "to solve this you do the following: \n" ); document.write( "----- \n" ); document.write( "multiply both sides by x to bring the x over to the right side of the equation and remove it from the denominator. \n" ); document.write( "----- \n" ); document.write( "you get: \n" ); document.write( "(20-4)/5 >= 16 * x \n" ); document.write( "which becomes: \n" ); document.write( "16/5 >= 16x \n" ); document.write( "----- \n" ); document.write( "divide both sides by 16 to get: \n" ); document.write( "16/(16*5) >= x \n" ); document.write( "this becomes: \n" ); document.write( "1/5 >= x \n" ); document.write( "to get x over to the left side of this equation you have to subtract x from both sides of this equation and to get 1/5 over to the right side of this equation you have to subtract 1/5 from both sides of this equation. \n" ); document.write( "you get: \n" ); document.write( "-x >= - (1/5) \n" ); document.write( "----- \n" ); document.write( "here's where the reversal of signs comes in. \n" ); document.write( "if you multiply both sides of this equation by (-1) you get: \n" ); document.write( "x <= (1/5) \n" ); document.write( "note the inequality was reversed. \n" ); document.write( "----- \n" ); document.write( "the answer to this question is that if x <= 1/5, then the original equation of 16/5x >= 16 holds true, assuming i interpreted the original equation correctly. \n" ); document.write( "----- \n" ); document.write( "if x = 1/5 = .2, this equation becomes 16/1 >= 16 which is true. \n" ); document.write( "if x = .3, this equation becomes 16/1.5 >= 16 which is false. \n" ); document.write( "if x = .1, this equation becomes 16/.5 >= 16 which is true. \n" ); document.write( "----- \n" ); document.write( "answer is x <= (1/5) \n" ); document.write( "-----\r \n" ); document.write( " \n" ); document.write( " \n" ); document.write( " \n" ); document.write( "\n" ); document.write( " \n" ); document.write( " |