Question

For solving pair of equation, in this exercise use the method of elimination by equating coefficients :
13x+ 11y = 70
11x + 13y = 74

Answer 1

13x + 11y = 70                        ...(1)
11x + 13y = 74                        ...(2)

Adding (1) and (2)
       13x + 11y = 70
+     11x + 13y = 74 
       24x + 24y = 144  
Dividing by 24,
   x + y = 6                             ....(3)

Subtracting (2) from (1)
       13x + 11y = 70
-     11x + 13y = 74  
       -     -          -       
       2x - 2y = - 4
Dividing by 2
         x - y = - 2                    ....(4)

Adding equation (3) and (4)
        x - y = - 2
   +  x + y = 6  
            2x = 4
              x = 2

From (3)
2 + y = 6
y = 4