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Solving Equations Using Method of Substitution

Solve the fol...

Question

Solve the following system of linear equations to find the value of $x$ .
$3 x - 2 y - 7 = 18$ and $- x + y = - 8$

-1

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Solution

The correct option is D 9
Given, $3 x - 2 y - 7 = 18$
$\Rightarrow 3 x - 2 y = 18 + 7$
$\Rightarrow 3 x - 2 y = 25$ ......(1)
$\Rightarrow - x + y = - 8$ ....(2)
On multiplying (2) by $2$ , we get
$\Rightarrow - 2 x + 2 y = - 16$ .....(3)
Adding (1) and (3), we get
$\Rightarrow x = 9$

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