{2x−y=92x+7y=17

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{2x−y=92x+7y=17

svartmaleJ · Accepted Answer

To solve a system of equations, you should use the substitution method or the elimination method. The substitution method should be used if one of the equations has a variable that can be easily solved for. The elimination method should be used if the equations have a variable term with the same or opposite coefficients or if neither equation can be easily solved for a variable.
The first equation can be easily solved for $y y$ but the equations have the same coefficient for the $x x$ terms so the elimination method will be easier to use.
To use the elimination method, subtract the two equations to eliminate the $x x$ terms. Then solve for y:
$2 x + 7 y = 17$
$- (2 x - y = 9)$
$8 y = 8$
$y = 1$
Now that you the value of y, substitute it into either equation and then solve for x:
$2 x - y = 9$
$2 x - 1 = 9$
$2 x = 10$
$x = 5$
The solution of the system is then $(x, y) = (5, 1) .$

{2x−y=9}{2x+7y=17}

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