Step-by-step explanation:
(X + y = 26) (-3)
3x + y = 56
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- 3 x - 3y = - 78 Note:cross 3x and-3x from both equations (they're opposite)
3x +y =56
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-3y +y = - 78 +56
-2y = - 22
[tex]y = \frac{ - 22}{ - 2} = 11[/tex]
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So we replace y in eq 2: (to obtain x)
3x + 11 =56
3x =45
X =15
