Question 621707
If you have a line that looks like
{{{ y = m*x + b[1] }}}, then a line perpendicular to it
looks like {{{ y = (-1/m )*x + b[2] }}} where {{{ m }}} is slope
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Your lines are
(1) {{{ y = 5 - 3x }}}
(2) {{{ 3x - y= 8 }}}
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(1) {{{ y = -3x + 5 }}}
and
(2) {{{ -y = -3x + 8 }}}
Multiply both sides by {{{-1}}}
(2) {{{ y = 3x - 8 }}}
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Now compare the slopes. They are
{{{ m[1] = -3 }}}
and
{{{ m[2] = 3 }}}
They can't be perpendicular because
{{{ m[1] = -m[2] }}} and to be perpendicular,
{{{ m[1] = -1/m[2] }}}