Question 1180054
<br>
The problem is poorly worded, so we don't really know what the question is that they are asking.<br>
To begin with, you can't add a number to an equation without changing the equation.  What you CAN do is add the SAME number to BOTH SIDES of an equation.<br>
To complete a square, you need to factor out the coefficient of the leading term and then use the pattern<br>
{{{(x+a)^2 = x^2+2ax+a^2}}}<br>
{{{2x^2+8x-5=0}}}
{{{2x^2+8x=-5}}}
{{{2(x^2+4x)=-5}}}<br>
Using the pattern above, we have to add "+4" inside the parentheses.  The expression in parentheses is being multiplied by 2, so we are adding 8 to the left side of the equation. So we can add 8 to BOTH SIDES of the equation to complete the square.<br>
{{{2(x^2+4x+4)=-5+8}}}
{{{2(x+2)^2=3}}}<br>
So with my interpretation of the question, the number I added TO BOTH SIDES OF THE EQUATION was 8.<br>