Show that each of the following systems of equations has a unique solution and solve it:

3x + 5y = 12, 5x + 3y = 4.

Given: 3x + 5y = 12 – eq 1


5x + 3y = 4 – eq 2


Here,


a1 = 3, b1 = 5, c1 = - 12


a2 = 5, b2 = 3, c2 = - 4


= , =


Here,


given system of equations have unique solutions.


Now,


In – eq 1


3x = 12 – 5y


X =


Substitute x in – eq 2


we get,


+ 3y = 4


= 4


60 – 25y + 9y = 12


60 – 16y = 12


16y = 60 – 12


16y = 48


y = = 3


y = 3


Now, substitute y in – eq 1


We get,


3x + 5×3 = 12


3x + 15 = 12


3x = 12 – 15


3x = - 3


x = = - 1


x = - 1


x = - 1 and y = 3


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