Question 756957
You have 2 simultaneous equations
(1) {{{ y = 5 }}}
(2) {{{ y = -5*tan(x) }}}
{{{ 0 < x < pi }}}
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By substitution, 
{{{ 5 = -5*tan(x) }}}
{{{ tan(x) = -1 }}}
In the 1st quadrant, the tan is positive.
In the 2nd quadrant, which is
{{{ pi/2 < x < pi }}}
The tan is {{{ -1 }}} at {{{ x = ( 3*pi) / 4 }}}
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The intersection is at ( 3pi/4 , 5 )