How do you solve $7x+y= 11$ and $3x+2y= -11$ using substitution?

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Answer 1 · 2018-03-30T08:35:45

$x = 3 and y =-10$

Rearrange the first equation to get:

$y = 11 - 7x$

Substitute this into the second equation:

$3x + 2(11 - 7x) = -11$

Expand the bracket:

$3x + 22 - 14x = -11$

$22 - 11x = -11$

$33 = 11x$

$x =3$

Now substitute $x = 3$ into any of the three equations to find $y$ :
$y = 11 - 7x$ $=>$ $y = 11 - 21$

$y =-10$

How do you solve 7x+y= 117x+y= 11 and 3x+2y= -113x+2y= -11 using substitution?