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