Question 1036503
{{{ 3x^2 + 9x - 30 = 0 }}}
You can complete the square to find roots
Divide both sides by {{{ 3 }}}
{{{ x^2 + 3x - 10 = 0 }}}
{{{ x^2 + 3x = 10 }}}
Take 1/2 of the coefficient of the {{{ x }}} term,
square it and add to both sides
{{{ x^2 + 3x + (3/2)^2 = 10 + (3/2)^2 }}}
{{{ x^2 + 3x + 9/4  = 10 + 9/4 }}}
{{{ x^2 + 3x + 9/4  = 49/4 }}}
{{{ ( x + 3/2 )^2 = ( 7/2 )^2 }}}
Take the square root of both sides
{{{  x + 3/2 = 7/2 }}}
{{{ x = 4/2 }}}
{{{ x = 2 }}}
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and, taking the negative square root of {{{ 49/4 }}}
{{{ x + 3/2 = -7/2 }}}
{{{ x = -10/2 }}}
{{{ x = -5 }}}
The roots are {{{ x = 2 }}} and {{{ x = -5 }}}
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Here's the plot of the given equation:
{{{ graph( 400, 600, -7, 4, -38, 5, 3x^2 + 9x - 30  ) }}}