Unformatted text preview: When there is a double set ofbrackets (a + b)(c + (1), then write the second set IRERJOWMHQCH?IMDIH}LEIBIhACEH?TS of brackets down twice and split the ﬁrst set up: Example: Example: Example: The expansion oftwo sets ofbrackets can be done more quickly using the FOIL method: Examples: (i) First term in bracket one >< First term in bracket two. (a + b)(c + d) = a(c+d)+b(c+d) = ac+ad+bc+bd (2x+ 3)(x +5) (4x—3Xx2—5x+2) (5—x)(2x+3) = 2x(x+5)+3(x+5)
2x2+10x+3x+15
2x2+13x+15 H 4xm2—5x+m—3o¥—5x+m
4x3—20x2+8x—3x2+15x—6 4x3—23x2+23x~6 5(2x+3)—x(2x+3)
10x+15—2x2—3x
15+7x—2x2 Outermost terms multiplied. Innermost terms multiplied.
Last of all. /§‘\ (2x+3)(x—5) W 2x2~10x+3x—15 2x2—7x—15 m
= (3x—5)(3x—5) i
, ,i =9x2—15x—15x+25: = 9x2—30x+25 l ; ‘ mummgpmwmmw u ...
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 Winter '10
 golishr

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