Răspunsuri

2014-09-21T15:14:56+03:00
(3x)^2+2*3x*1+1-(x^2+2*x*3+9)=
9x^2+6x+1-x^2-6x-9=
8x^2-8=
8(x^2-1)=
8(x-1)(x+1)




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2014-09-21T15:17:43+03:00
(3x+1)^2 - (x+3)^2 = [ (3x)^2 + 2。3x 。1+ 1^2 ] - [ x^2 + 2 。x。3 + 1^2 ] = ( 9x^2 + 6x + 1 ) - ( x^2 + 6x + 9 ) = 9x^2 + 6x+1 - x^2 -6x-9 = 8x^2 - 8 = 8 。( x^2 + 1) . Nu stiu cat de corect este. 
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