how do i solve for this system of equations
11x-3y=-36
12y-9x=39
?
tried reordering the terms but what else?
The alternative method (the method used for more equations with more unknowns) is the elimination method...
$\displaystyle 11x - 3y = -36$
$\displaystyle -9x + 12y = 39$.
Multiply the first equation by 4 to give
$\displaystyle 44x-12y=-144$
$\displaystyle -9x+12y=39$
Add the equations together
$\displaystyle (44x-12y)+(-9x+12y)=-144+39$
$\displaystyle 35x=-105$
$\displaystyle x = -3$.
Substitute into one of the original equations...
$\displaystyle 11(- 3) - 3y = -36$
$\displaystyle -33- 3y = -36$
$\displaystyle -3y = -3$
$\displaystyle y = 1$
So the solution is $\displaystyle (x,y) = (-3,1)$.