( a + b ) 2 = a 2 + 2ab + b 2 ( a – b ) 2 = a 2 - 2ab + b 2 a 2 – b 2 = ( a + b)( a – b )

( a + b )2 = a2 + 2ab + b2 ( a – b )2 = a2 - 2ab + b2 a2 – b2 = ( a + b)( a – b )

Contoh : 1. ( x + 4 )2 = ....2. ( 2x – 1 )2 = ....Jawab : 1. ( x + 4 )2 = x2 + 8x + 16 (x2) (2)(x)(4) (4)2 2. ( 2x – 1 )2 = 4x2 - 4x + 1 (2x)2 – (2)(2x)(1) + (-1)2 • Coba ya ? • 1. ( x – 3 )2 = .... • 2. ( 3x + 2 )2 = ....

Contoh :1. a2 – 36 = ....2. 25x2 – 81y2 = ....Jawab : 1. a2 – 36 = ( a + 6 )( a – 6 ) 2. 25x2 – 81y2 = ( 5x + 9y )( 5x – 9y) • Try this ...... • 1. m2 – 49 = .... • 2. 16k2 – 4p2 = ....

Bentuk ax2+bx+c jika a = 1 memiliki faktor-faktor ( x+p ) dan ( x+q ) jadi ax2+bx+c = x2 + ( p+q )x + pq

Contoh :Faktorkanlah :1. x2 + 5x + 6 = ....2. a2 – a – 12 = ....Jawab :1. x2 + 5x + 6 = x2 + ( p + q ) x + pq p + q = 5 dan pq = 6 maka p = 2, q = 3 x2 + 5x + 6 = ( x + 2 )( x + 3 ) 2. a2 – a – 12 = a2 + ( p + q ) a + pq p + q = - 1 dan pq = -12 maka p = - 4, q = 3 a2 – a – 12 = ( a – 4 )( a + 3 )

Latihan :Faktorkanlah :1. w2 + 9w + 20 = ....2. h2 – 10h + 24 = ....3. p2 + p – 6 = ....4. y2 – 2y – 15 = ...

Bentuk ax2+bx+c jika a ≠ 1acax2 + bx + c = ax2 + px + qx + cp qcatatan :p x q = a x c dan p + q = b

Faktorkanlah:1. 2x2 + 10x – 15 2. 6x2 – 4x + 10

( a + b ) 2 = a 2 + 2ab + b 2 ( a – b ) 2 = a 2 - 2ab + b 2 a 2 – b 2 = ( a + b)( a – b )