Multiplying Out Brackets Double Brackets What Do Double

Multiplying Out Brackets. Double Brackets.

What Do Double Brackets Represent? Consider the area of this rectangle. 2 x A 1 = 3 2 x 2 A 2 = 12 x A 3 = 3 x A 4 = 18 A 1 A 2 A 3 A 4 x 6 Total Area = 2 x 2 + 12 x +3 x +18 Final Answer = 2 x 2 + 15 x +18

How To Multiply Out A Double Bracket. Consider: ( 2 x + 3 ) ( x + 6) =2 (x + 6 )+3( X + 6) x Golden Rule: Everything in the first bracket multiplies the second bracket. = 2 x 2+ + + 12 x 3 x 18 = + + 2 x 2 15 x 18 The same as the area of the rectangle.

What Goes In The Box? (4 x + 3 ) ( 5 x + 6) = 4 x ( 5 x + 6) +3 =20 x 2 +24 x +15 x =20 x 2 +39 x +18 ( 5 x + 6) +18

Dealing With Negatives & Positives. You should know that : +x+ + = +x-=-x+=-x-= + When you multiply. If the signs are the same you get a plus if they are different you get a negative. Now try these: (1) 4 x – 3 -12 = (2) – 2 x – 5 10 = (3) - 7 x 2 -14 = (4) 6 x 8 = 48 (6) 4 + – 3 1 = (7) 4 – – 3 7 = (8) – 5 – + 7 -12 = (9) 6 + – 3 3 = (5) – 6 x – 54 (10) – 5 – – -1 9= 4=

Brackets With Negatives & Positives. Using the rules you have just seen complete the following. ( 2 x – 7 ) ( 5 x – 4) = 2 x( 5 x – -7 ( 5 x – 4) 4) 2 =10 x - 8 x - 35 x + 28 =10 x 2 - 43 x + 28

What Goes In The Box? ((3 x – 4 ) ( 6 x – 7) = 3 x ( 6 x – 7 ) =18 x 2 21 x =18 x 2 45 x -4 24 x +28 ( 6 x – 7 ) +28

What Goes In The Box? ( 2 x + 4 ) ( 3 x – 8 ) = 6 x 2 ( 3 x - 8 ) -16 x + 4 +12 x = 6 x 2 -4 x -32 = 2 x ( 3 x - 8 ) -32