Question 970261
Plot the height, {{{ h }}} on the verical axis and
hours, {{{ t }}} on the horizontal axis
You are given 2 points on the line in the format
( t , h )
( 8, 26.4 )
( 26, 22.8 )
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Find equation of the line using point-slope formula
{{{ ( h - 22.8 ) / ( t - 26 ) = ( 26.4 - 22.8 ) / ( 8 - 26 ) }}}
{{{ ( h - 22.8 ) / ( t - 26 ) = 3.6 / ( -18 ) }}}
{{{ ( h - 22.8 ) / ( t - 26 ) = -.2 }}}
{{{ h - 22.8 = -.2*( t - 26 ) }}}
{{{ h =- .2t + 5.2 + 22.8 }}}
{{{ h = -.2t + 28 }}}
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Find {{{ h }}} after {{{ 20 }}} hrs
{{{ h = -.2*20 + 28 }}}
{{{ h = 24 }}}
The height is 24 cm after 20 hrs
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check the equation:
does it go through ( 8, 26.4 ) ?
{{{ h = -.2t + 28 }}}
{{{ h = -.2*8 + 28 }}} 
{{{ h = -1.6 + 28 }}}
{{{ h = 26.4 = 26.4 }}}
OK -you can check other point