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Exercise 12⋅ 2
Solve by the method of substitution (1 - 3) :

1. 7 x 3 y 31
   9 x 5 y 41
   2. 1
   2 3



x y

1

3 2



x y

3.  2
   b

y

a

x

axby a^2 b^2

Solve by the method of elimination (4 - 6) :

4. 7 x 3 y 31 5. 7 x 8 y  9 6. axby c
   9 x 5 y 41 5 x 4 y  3 a^2 xb^2 y c^2
   Solve by the method of cross-multiplication (7 - 15) :


5. 2 x 3 y 5 0 8. 3 x 5 y 9 0 9. x 2 y 7
   4 x 7 y 6 0 5 x 3 y 1 0 2 x 3 y 0


6. 4 x 3 y  12 11.  7 x 8 y 9 12. 3 xy 7 0 2 xy 3
   2 x 5 5 x 4 y  3


7. axby a^2 b^2 14. y( 3 x) x( 6 y)
   2 bxay ab^3 ( 3 x) 5 (y 1 )^


8. (x 7 )(y 3 ) 7 (y 3 )(x 1 ) 5