How do you solve -4x+9y=9 and x-3y= -6?

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Answer 1 · 2018-03-15T15:49:17

See below.

$4x+9y=9 " " " "(1)$

$x-3y= -6 " " " "(2)$

From equation $(2)$

$x-3y=-6$

$=> x = -6+3y " " " "(3)$

Substituting in equation $(1)$

$=> 4(3y-6)+9y=9$

$=>12y-24+9y=9$

$=>21y=9+24$

$=>21=33$

$=>y=33/21$

$=>y=11/7$

Substituting the value of $y$ in equation $(2)$

$x=3y-6$

$=> x=3(11/7)-6$

$=> x=33/7-6$

$=> x = (33-42)/7$

$=> x=-9/7$

So

$x=-9/7 and y=11/7$