Solve these simultaneous equations, (1) [5a - 3b = 16], (2) [2b - 3a = -9] ?

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(1) 5a - 3b = 16
(2) 3b - 3a = -9

First make either the a's or b's same.in one of the equations.

(1) x 2 = 10a - 6b = 32  
(2) x 3 = 6b - 9a = -27

Second combine the equations.

(1) + (2) 

--> 10a - 6b + 6b - 9a = 32-27 

--> 10a - 9a = 32 -27 

--> a = 5

Third use (1) and a = 5 to find b.

(5 x 5) - 3b = 16

--> 25 - 3b = 16

--> 25 - 16 = 3b 

--> 9 = 3b 

--> b = 3

Ivan T. A Level Biology tutor, GCSE Biology tutor, A Level Chemistry ...

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