The given set of equation is
-3x -2y =13 --------------(1)
and
7x -7y = -3 --------------(2)
Make the coefficient of any one variable same in both equations.
So we will multiply equation(1) by 7 and equation (2) by 3
(1) x 7 gives :
- 21x -14y = 91
(2) x 3 gives:
21x - 21y = -9
Now, as the coefficients of x in both the new equations are same but opposite in sign, we will add the two equations so that x gets eliminated and we can find value of y
(- 21x -14y = 91 )
+ (21x - 21y = -9)
That gives :
-35 y = 82
y = - 82 / 35
Substituting this value of y in any one equation , we can find value of x
-3x -2y =13 --------------(1)
-3x -2(-82/ 35) =13
-3x + (164/35) =13
-3x = 13 - (164/35)
-3x =( (13)*(35) - (164))/ 35
-3x =( 455 - 164)/ 35
-3x =( 291)/ 35
x =( 291)/ (35 * (-3))
x = - ( 97)/ (35)
Therefore x = - ( 97)/ (35) and y = - 82 / 35
