SOME BASIC ALGEBRAIC FORMULAE:

                         

                                   SOME BASIC ALGEBRAIC FORMULAE:

1.(a + b)2 = a2 + 2ab+ b2

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

3.(a + b)3 = a3 + b3+ 3ab(a + b)

4. (a - b)3 = a3 - b3- 3ab(a - b)

5.(a + b + c)2 = a2 + b2 + c2+2ab+2bc +2ca

6.(a + b + c)3 = a3 + b3 + c3+3a2b+3a2c + 3b2c +3b2a +3c2a +3c2a+6abc

7.a2 - b2= (a + b)(a – b ) 
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8.a3 – b3= (a – b) (a2 + ab + b2)

9.a3 + b3= (a + b) (a2 - ab + b2)

10.(a + b)2+ (a - b)2= 4ab.

11.(a + b)2- (a - b)2= 2(a2 + b2)

12.If a + b +c =0, then a3 + b3 + c3= 3abc