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Which of the following values of x and y satisfy the following equations i and ii?
i. 3x + y = 19
ii. x - y = 9

1-7, -2
2-7, 2
37, -2
47, 2

Answer:- 1

Explanation:-

Solution:

\begin{aligned} 3 x + y = 19 . . . . . (i) \\ x - y = 9 . . . . . (i i) \\ Adding (i) and (ii), \\ we get \\ 4 x = 28 \\ x = 7 \\ Putting x =  7 in (i), \\ we get \\ 3 x + y = 19 \\ 21 + y = 19 \\ y = 19 - 21 = - 2 \\ Answer is 7, - 2 \end{aligned}

$\eqalign{ & {\text{3}}x + y = 19\,.....(i) \cr & x - y = 9\,.....(ii) \cr & {\text{Adding (i) and (ii),}} \cr & {\text{we get }} \cr & {\text{4}}x = 28 \cr & x = 7 \cr & {\text{Putting }}x\,{\text{ = 7}}\,{\text{in (i),}} \cr & {\text{we get }} \cr & 3x + y = 19 \cr & 21 + y = 19 \cr & y = 19 - 21 = - 2 \cr & {\text{Answer is 7, }} - {\text{2}} \cr}$

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", "dateCreated": "7/24/2019 10:09:12 AM", "author": { "@type": "Person", "name": "Nitin Sir" } }, "suggestedAnswer": { "@type": "Answer", "text": "

Solution:

\begin{aligned} 3 x + y = 19 . . . . . (i) \\ x - y = 9 . . . . . (i i) \\ Adding (i) and (ii), \\ we get \\ 4 x = 28 \\ x = 7 \\ Putting x =  7 in (i), \\ we get \\ 3 x + y = 19 \\ 21 + y = 19 \\ y = 19 - 21 = - 2 \\ Answer is 7, - 2 \end{aligned}

$\eqalign{ & {\text{3}}x + y = 19\,.....(i) \cr & x - y = 9\,.....(ii) \cr & {\text{Adding (i) and (ii),}} \cr & {\text{we get }} \cr & {\text{4}}x = 28 \cr & x = 7 \cr & {\text{Putting }}x\,{\text{ = 7}}\,{\text{in (i),}} \cr & {\text{we get }} \cr & 3x + y = 19 \cr & 21 + y = 19 \cr & y = 19 - 21 = - 2 \cr & {\text{Answer is 7, }} - {\text{2}} \cr}$ ", "dateCreated": "7/24/2019 10:09:12 AM" } }

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