document.write( "Question 28176: how do you solve? m^2 + m - 72 = 0 \n" ); document.write( "
Algebra.Com's Answer #15361 by sdmmadam@yahoo.com(530)![]() ![]() ![]() You can put this solution on YOUR website! m^2 + m - 72 = 0----(1) \n" ); document.write( "m^2 + [(9m) +(-8m)] - 72 = 0 \n" ); document.write( "[m^2+9m]-8m-72=0 (by additive associativity) \n" ); document.write( "m(m+9)-8(m+9) = 0 \n" ); document.write( "mp -8p = 0 where p = (m+9) \n" ); document.write( "p(m-8) = 0 \n" ); document.write( "(m+9)(m-8)=0 \n" ); document.write( "(m+9) = 0 gives m = -9 \n" ); document.write( "(m-8) = 0 gives m = 8 \n" ); document.write( "Answer: m = -9 and m = 8 \n" ); document.write( "Put m=-9 on the LHS of (1)and get 81-9-72 = 0 =RHS \n" ); document.write( "m= 8 on the LHS of (1)and get 64+8-72 = 0 =RHS \n" ); document.write( "Therefore our values m = -9 and m = 8 are correct\r \n" ); document.write( "\n" ); document.write( "NOTE: \n" ); document.write( "[The golden rule is: write the mid term as the sum of two terms whose product is the product of the square term and the constant term] \n" ); document.write( "[HOW? Multiply the square term and the constant term: (m^2)X(-72) = -72m^2 \n" ); document.write( "And (-72) = -(1X2X2X2X3X3) = (9)X(-8) so that the mid term: (m) =[(9m) +(-8m)] and the product of these two parts:(9m) and (-8m) = -72m^2 using the concept \n" ); document.write( "If the sign of the product is minus, and the middle term if +,then give the sign of the midterm to the larger set and the other sign to the smaller. \n" ); document.write( " \n" ); document.write( " |