4. X 2 + 6x – 7 = 0 X 2 + 6x = 7 ← pindah 7 ke kanan (x+3) 2 – 9 = 7 ← menyempurnakan kuasa dua (x+3) 2 = 7 + 9 ← pindah 9 ke kanan (x+3) 2 = 16 X+ 3 = 4 @ - 4 ← ambil punca kuasa dua X= 4 - 3 @ - 4 – 3 ← setiap satu tolak 3 X = 1 @ - 7
5. Kaedah menyempurnakan kuasa dua x 2 + 2 x + 1 = ( x+1) 2 -> x 2 + 4 x + 4 = ( x+2) 2 -> x 2 + 6 x + 9 = ( x+3) 2 -> x 2 + 8 x + 16 = ( x+4) 2 -> x 2 + 16 x + 64 = ( x+8) 2 -> x 2 + 2 x = ( x + 1 ) 2 – 1 x 2 + 4 x = ( x + 2 ) 2 – 4 x 2 + 6 x = ( x + 3 ) 2 – 9 x 2 + 8 x = ( x + 4 ) 2 – 16 x 2 + 16 x = ( x + 8 ) 2 - 64
6. Kaedah menyempurnakan kuasa dua x 2 - 2 x + 1 = ( x-1) 2 -> x 2 - 4 x + 4 = ( x-2) 2 -> x 2 - 6 x + 9 = ( x- 3) 2 -> x 2 - 8 x + 16 = ( x- 4) 2 -> x 2 - 16 x + 64 = ( x- 8) 2 -> x 2 - 2 x = ( x - 1 ) 2 – 1 x 2 - 4 x = ( x - 2 ) 2 – 4 x 2 - 6 x = ( x - 3 ) 2 – 9 x 2 - 8 x = ( x - 4 ) 2 – 16 x 2 - 16 x = ( x - 8 ) 2 - 64