... (3x) 2 – 2. 3xy + y 2 = (3x – y) 2 c) 25 a 2 +4b 2 +20 ab = (5a) 2 + 2. 5 2ab + (2b) 2 = (5a + 2b) 2 d) x 2 – x + 14 = x 2 – 2. 1 2 x + (1 2 ) 2 = (x - 1 2 ) 2 0,50 ,25 0 ,25 0 ,25 0 ,25 0 ,25 0 ,25 3a) ... -2xy + y 2 ).( x – y ) = x.( x 2 -2xy + y 2 ) – y.( x 2 -2xy + y 2 ) = x3 – 2x 2 y + xy 2 – x 2 y + 2xy 2 – y3 0 ,25 0 ,25 0 ,25 0 ,25 2 a) y 2 + 2y + 1 = ( y + 1) 2 b) 9x 2 +y 2 – 6xy ... x 2 + 7x + 12 = x 2 + 3x + 4x + 12 = (x 2 + 3x) +(4x + 12) = x(x +3 ) + 4(x + 3) = (x + 3)( x + 4 ) 0,50 ,25 0 ,25 0 ,25 0 ,25 0 ,25 0 ,25 a) x(x -2) + x -2 = 0 x(x – 2) +(x - 2) (x – 2) (x...