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Solve the following pair of linear equations :
$31x+43y-117 = 0$; $43x + 31y = 105$
$31x+43y-117 = 0$; $43x + 31y = 105$
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Solution:
(a)
$31x + 43y = 117$ ........ (i)
$43x + 31y = 105$ ........ (ii)
Adding (i) and (ii) we get
$74x + 74y = 222 \Rightarrow x + y = 3$ ............(iii) (1 Mark)
Subtracting (i) and (ii) we get
$-12x + 12y = 12$ or $- x + y = 1$ ............(iv) (1 Mark)
Solving (iii) and (iv) $x = 1, y = 2$ (1 Mark)
(a)
$31x + 43y = 117$ ........ (i)
$43x + 31y = 105$ ........ (ii)
Adding (i) and (ii) we get
$74x + 74y = 222 \Rightarrow x + y = 3$ ............(iii) (1 Mark)
Subtracting (i) and (ii) we get
$-12x + 12y = 12$ or $- x + y = 1$ ............(iv) (1 Mark)
Solving (iii) and (iv) $x = 1, y = 2$ (1 Mark)