Question 48976
{{{7x^2-9=16}}}[Set the equation equal to zero by subtracting 16 from both sides]
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{{{7x^2 - 25 = 0}}}
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{{{7x^2 + 0x - 25 = 0}}} [Add the term (0x) to make it easier to work with]
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{{{7x^2 + 0x - 25 = 0}}}  
a=7
b=0
c=-25

{{{x =  (-0 +- sqrt( 0^2-(4)(7)(-25) ))/((2)(7)) }}}   [Plug-in the values]


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{{{x = (-0 +- sqrt( -(4)(7)(-25) ))/((14))) }}} [Simplify]
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{{{x = (-0 +- sqrt( 700) ))/((14))) }}}
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{{{x = (-0 +- 26.4575)/((14)))) }}}
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x = +26.4575/14 = 1.8898
x = -26.4747/14 = -1.8898