<span>x^2 + 8x = -3
</span><span>x^2 + 8x + 16 = -3 + 16
using a^2 + 2 a b + b^2 = (a+b)^2
</span><span>
</span>x^2 + 8x + 16 = 13
<span>(x +4)^2 = 13
answer : 16 is the number </span><span>you must add to complete the square</span>
Rounded to 1 decimal place
