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Consider this equation;

$$ 3x^2 + 2dx - d^2 = 0 $$

Now I need to find the value of x.I've consider using the quadratic formula but I've got 2 squared terms. I've also tried forming the equation to get x squared on one side, but than I'm not sure what to next. Any help on this?

Thank you!

Onkar Dahale
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codeisfun
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2 Answers2

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$3x^2 + 2dx - d^2=3(x+d)(x-d/3)$ so $x=-d$ or $x=d/3$

Laassila souhayl
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If the question is to solve $3x^2+2dx-d^2=0$ for $x$ you can just apply the quadratic formula, getting $$x=\frac {-2d \pm \sqrt{4d^2-4 \cdot 3 \cdot (-d^2)}}{2 \cdot 3}=\frac {-2d\pm 4d}6=\frac d3,-d$$

Ross Millikan
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  • Wait I can apply the quadratic formula here, but how? I have 2 square terms and no c term,the term that isnt squared or has an x component? – codeisfun Dec 12 '20 at 14:53
  • Yes. The $c$ term of your expression is $(-d^2)$. In general, when you are solving for $x$ it is all the stuff that does not have a factor of $x$. If you are solving for $x$, $d$ is a constant which specifies the problem. – Ross Millikan Dec 12 '20 at 14:56
  • Oh okay so we can look at that way. Thank you for your help! – codeisfun Dec 12 '20 at 15:00