Question 1025727
Define the points of intersection:
x-intercept: ( 80,0 )
y-intercept: ( 0, -90 )
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Use the general point-slope formula
{{{ ( y - (-90) ) / ( x - 0 ) = ( 0 -(-90) ) / ( 80 - 0 ) }}}
{{{ ( y + 90 ) / x = 90 / 80 }}}
{{{ ( y + 90 ) / x = 9/8 }}}
multiply both sides by {{{ 8x }}}
{{{ 8*( y + 90 ) = 9x }}}
{{{ 8y + 720 = 9x }}}
{{{ 8y = 9x - 720 }}}
{{{ y = (9/8)*x - 90 }}}
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check answer:
does it go through ( 80,0 ) ?
{{{ y = (9/8)*x - 90 }}}
{{{ 0 = (9/8)*80 - 90 }}}
{{{ 0 = 90 - 90 }}}
{{{ 0 = 0 }}}
OK
does it go through ( 0, -90 ) ?
{{{ y = (9/8)*x - 90 }}}
{{{ -90 = (9/8)*0 - 90 }}}
{{{ -90 = -90 }}}
OK