Question 820877
The form of the general point-slope equation is:
{{{ y = m*x + b }}}
{{{ m }}} = the slope of the line
{{{ b }}} = the y-intercept
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The slope is always m = ( change in y ) / ( change in x )
In the following formula, {{{ y }}} is ANY {{{ y }}}
and {{{ x }}} is ANY {{{ x }}}
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given the point (-11,-3) and {{{ m=-9 }}}
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{{{ ( y -(-3) ) / ( x -(-11) ) = -9 }}}
This is just ( change in y ) / ( change in x ) = m
{{{ ( y + 3 ) / ( x + 11 ) = -9 }}}
{{{ y + 3 = -9*( x + 11 ) }}}
{{{ y + 3 = -9x - 99 }}}
{{{ y = -9x - 102 }}}
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This is now in the form {{{ y = m*x + b }}}
check: does it go through the point ( -11,-3 )?
{{{ -3 = -9*(-11) - 102 }}}
{{{ -3 = 99 - 102 }}}
{{{ -3 = -3 }}}
OK
Here's a plot of the line:
{{{ graph( 400, 400, -16, 6, -120, 20, -9x - 102 ) }}}