Question 821615
Plot {{{ v }}} = min/day on the horizontal axis
Plot {{{ G(v) }}} = GPA on the vertical axis
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You are given 2 points on the line:
( 85, 2.85 ) and
( 155, 2.05 )
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Use the general point-slope formula:
{{{ ( G - 2.05 ) / ( v - 155 ) = ( 2.85 - 2.05 ) / ( 85 - 155 ) }}}
{{{ ( G - 2.05 ) / ( v - 155 ) = .8 / ( -70 ) }}}
{{{ ( G - 2.05 ) / ( v - 155 ) = -8/700 }}}
{{{ G - 2.05 = ( -8/700 )*( v - 155 ) }}}
{{{ 700*( G - 2.05 ) = -8*( v - 155 ) }}}
{{{ 700G - 1435 = -8v + 1240 }}}
{{{ 700G = -8v + 2675 }}}
{{{ G = -.0114v + 3.821 }}}
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check:
does it go through ( 85,2.85 )?
{{{ G = -.0114v + 3.821 }}}
{{{ 2.85 = -.0114*85 + 3.821 }}}
{{{ 2.85 = -.969 + 3.821 }}}
{{{ 2.85 = 2.852 }}}
( error due to rounding off? )
You can test the other point
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(b)
The slope is the drop in GPA for each additional minute
played on video games
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Here's the plot:
{{{ graph( 400, 400, -20, 350, -1, 5, -.0114x +3.821 ) }}}
As you can see, if you play about 6 hours a day,
your GPA drops to zero