Question 559301
(1) {{{ -2x-y = -9 }}}
(2) {{{ 5x-2y = 18 }}}
Multiply both sides of (1) by {{{ 2 }}}
and subtract (1) from (2)
(2) {{{ 5x-2y = 18 }}}
(1) {{{ 4x+ 2y = 18 }}}
{{{ 9x = 36 }}}
{{{ x = 4 }}}
and
(1) {{{ -2*4-y = -9 }}}
(1) {{{ -y = -9 + 8 }}}
(1) {{{ -y = -1 }}}
(1) {{{ y = 1 }}}
The solution is (4,1)
Here's a plot of the 2 equations:
{{{ graph( 400, 400, -5, 10, -12, 12, -2x + 9, (5/2)*x - 9 ) }}}