Solve for k
k=3
k=-3
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k^{2}-9=0
Divide both sides by 16.
\left(k-3\right)\left(k+3\right)=0
Consider k^{2}-9. Rewrite k^{2}-9 as k^{2}-3^{2}. The difference of squares can be factored using the rule: a^{2}-b^{2}=\left(a-b\right)\left(a+b\right).
k=3 k=-3
To find equation solutions, solve k-3=0 and k+3=0.
16k^{2}=144
Add 144 to both sides. Anything plus zero gives itself.
k^{2}=\frac{144}{16}
Divide both sides by 16.
k^{2}=9
Divide 144 by 16 to get 9.
k=3 k=-3
Take the square root of both sides of the equation.
16k^{2}-144=0
Quadratic equations like this one, with an x^{2} term but no x term, can still be solved using the quadratic formula, \frac{-b±\sqrt{b^{2}-4ac}}{2a}, once they are put in standard form: ax^{2}+bx+c=0.
k=\frac{0±\sqrt{0^{2}-4\times 16\left(-144\right)}}{2\times 16}
This equation is in standard form: ax^{2}+bx+c=0. Substitute 16 for a, 0 for b, and -144 for c in the quadratic formula, \frac{-b±\sqrt{b^{2}-4ac}}{2a}.
k=\frac{0±\sqrt{-4\times 16\left(-144\right)}}{2\times 16}
Square 0.
k=\frac{0±\sqrt{-64\left(-144\right)}}{2\times 16}
Multiply -4 times 16.
k=\frac{0±\sqrt{9216}}{2\times 16}
Multiply -64 times -144.
k=\frac{0±96}{2\times 16}
Take the square root of 9216.
k=\frac{0±96}{32}
Multiply 2 times 16.
k=3
Now solve the equation k=\frac{0±96}{32} when ± is plus. Divide 96 by 32.
k=-3
Now solve the equation k=\frac{0±96}{32} when ± is minus. Divide -96 by 32.
k=3 k=-3
The equation is now solved.
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Limits
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