Expansion, Rev | Scoins.net | DJS

## Expansion, Rev

ALGEBRA                        20040115

Each of these lines of algebra has two errors. Write the correct lines of algebra out in your book. Enough is left correct in nearby questions for you to use as hints. Some people prefer to ignore the ‘wrong’ right hand side: don’t ignore it completely.

1     (x + 12) (x – 11)       =   x²   - 23x – 23

2     (x²  + 7) (x²  + 17)     =   2 x²   +24 x²   + 85

3     (3x² +17) (17x² - 3)  =   51 x   -  85

4     (x  +  y)  (y  -  x )        =    x²   +  xy  + y²

Complete these common phrases that I use in lessons: you should be able to remember these very easily.

5A    sum times a difference is the ______________ of two __________

6A       _______ times a ________ makes a  ________

7     This plus That all _____________                                                          (my favourite haiku)

is this ______________ plus __________ squared plus

________ times __________ times __________

8        No __________ No Marks                                                                                      (NWNM)

Apply your algebra skills to do these remaining problems without a calculator. Show this (NWNM) by factorising, using brackets, etc and write these in your book                   hint

9         593 x 7411  +  407 x 7411 =                                                                                factorise

10       126 x²    –     74 x² =                                                                                                      Q5

11       173 ²      –     127 ² =                                                                                                  Q5

12       (2007) ² =                                                                                                        Square x=2000, y=7

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