Question 1191936
<pre>

I'll do one, you can do the other two.

Midpoint_AC is at  ( {{{ (8+(-2))/2 }}} , {{{ (5+3)/2 }}} ) or  (3,4)

Now the slope from this midpoint to vertex B is:  {{{ (4+5)/(3-6) }}} = -3

We can use  point-slope form  {{{ y - y[0] = m(x - x[0]) }}}  where ( {{{x[0]}}}, {{{y[0]}}} )   is any point on that line.

Using vertex B, and slope = -3:
{{{ y + 5 = -3 (x - 6) }}}
{{{ y + 5 = -3x + 18 }}}   <--- point-slope form

If slope-intercept form is needed, move the 5 over:
{{{ y = -3x + 13 }}}    <--- slope-intercept form


The two others can be done similarly.