Question 313374
Put both lines in slope-intercept form, {{{y=mx+b}}}
{{{5y=4x+10}}}
{{{y=(4/5)x+2}}}
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.
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{{{4y=-5x+4}}}
{{{y=-(5/4)x+1}}}
Parallel lines have identical slopes, which is not the case here.
Perpendicular line have slopes that are negative reciprocals.
{{{m1*m2=-1}}}
{{{(4/5)(-(5/4))=-1}}}
The lines are perpendicular.
{{{ graph( 300,300, -5, 5, -5, 5, (4/5)x+2, -(5/4)x+1) }}}