Question 452488
{{{ 2x + 9y = 20 }}}
{{{ x = 8 - 4y }}}
{{{ 2*(8 - 4y) + 9y = 20 }}}
{{{ 16 - 8y + 9y = 20 }}}
{{{ y = 4 }}}
and
{{{ x = 8 - 4y }}}
{{{ x = 8 - 4*4 }}}
{{{ x = -8 }}}
check answers:
{{{ 2x + 9y = 20 }}}
{{{ 2*(-8) + 9*4 = 20 }}}
{{{ -16 + 36 = 20 }}}
{{{ 20 = 20 }}}
OK