Question 1106126
Any line parallel to L1 will have the same slope
{{{ m[2] = m[1] }}}
{{{ m[2] = -3/4 }}}
The slope of L2 is {{{ -3/4 }}}
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Any line perpendicular to L1 will have slope
{{{ m[3] = -1/m[1] }}}
{{{ m[3] = -1/(( -3/4)) }}}
{{{ m[3] = 4/3 }}}
The slope of L3 is {{{ 4/3 }}}