Question 679223
Starting with
{{{x^2+16x = -3}}}
Yes, add 3 to both sides.
{{{x^2+16x+3=0}}}
...
If you are completing the square, then
take half of b and square it.
In this case, b is 16, half of 16 is 8 and 8 squared is 64.
Add 64 to both sides.
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{{{x^2 + 16x + 64 = -3 + 64}}}
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{{{(x+8)^2 = 61}}}
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{{{sqrt(x+8)^2}}} = +/- {{{sqrt(61)}}}
...
x + 8 = +/- {{{sqrt(61)}}}
x = {{{-8+-sqrt(61)}}}

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