document.write( "Question 29685: 5x(squared) - 2x + 1 = 0 \n" ); document.write( "
Algebra.Com's Answer #16415 by sdmmadam@yahoo.com(530)![]() ![]() ![]() You can put this solution on YOUR website! 5x(squared) - 2x + 1 = 0 \n" ); document.write( "5x^2-2x+1= 0 ----(1) \n" ); document.write( "x= {-(-2)+ or - sqrt[(-2)^2-4X5X1]}/2X5 \n" ); document.write( "[ using given ax^2+bx+c = 0, then x={-b+or-sqrt(b^2-4ac)}/2a ] \n" ); document.write( "x = (1/10){2+or-sqrt[4-20]} \n" ); document.write( "=(1/10){2+or-(4i)} (sqrt(-16) = sqrt[16i^2]= sqrt4^2i^2]=4i) \n" ); document.write( "Therefore x = (1/10)(2+4i) or x = (1/10)(2-4i) \n" ); document.write( "That is x = (1+2i)/5 and x = (1-2i)/5 (cancelling 2 in the nr and in the dr) \n" ); document.write( "Verification: Putting x = (1+2i)/5 in (1) \n" ); document.write( "LHS = 5x^2-2x+1 \n" ); document.write( "= 5[(1+2i)^2]/25 - 2(1+2i)/5 +1 \n" ); document.write( "=(1/5)[1+4i^2+4i-2-4i+5] \n" ); document.write( "=(1/5)[1-4+4i-2-4i+5] \n" ); document.write( "=(1/5)[6-6+4i-4i] \n" ); document.write( "=(1/5)X(0) \n" ); document.write( "=0 =RHS \n" ); document.write( "Since this complex root holds and as complex roots occur in conjugate pairs,there is no need to try the validity of the other complex root\r \n" ); document.write( "\n" ); document.write( " \n" ); document.write( " |