Question 911737
{{{ 2x^2 + 8x - 7 = -2 }}}
{{{ 2x^2 + 8x = 5 }}}
{{{ x^2 + (8/2)*x = 5/2 }}}
Take {{{ 1/2 }}} of the coefficient
of the x term, square it and add
it to both sides
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{{{ x^2 + 4x + (4/2)^2 = 5/2 + ( 4/2)^2 }}}
{{{ x^2 + 4x + 4 = 5/2 + 8/2 }}}
{{{ x^2 + 4x + 4 = 13/2 }}}
{{{ ( x + 2 )^2 = 13/2 }}}
Take the square root of both sides
{{{ x + 2 = sqrt( 13/2 ) }}}
{{{ x = ( -4 + sqrt(13) ) / 2 }}}
and also:
{{{ x = ( -4 - sqrt(13) ) / 2 }}}
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Check my math carefully
Plug either answer back into the
original equation and solve