Question 30571
{{{ 6x-3y=30 }}} and {{{ 4x=2-y }}} then find x+y
get the second equation in y=mx+b format
{{{ 4x=2-y }}} add y to both sides
{{{ 4x+y=2 }}} subtract 4x from both sides
{{{ y=-4x+2 }}} Plug this into the first equation
{{{ 6x-3(-4x+2)=30 }}} distribute the -3
{{{ 6x+12x-6=30 }}} Add 6 to both sides
{{{ 6x+12x=30+6 }}} Combine like terms
{{{ 18x=36 }}} divide by 18
{{{ x = 2 }}}
Plug this back into the second equation
{{{ 4(2)=2-y }}}
{{{ 8=2-y }}} subtract 2 from both sides
{{{ 6 = -y }}} negative variables is a no no .... change all the signs
{{{ -6 = y }}}
Plug x and y into x+y
{{{ x+y }}}
{{{2+-6}}}
{{{-4}}}