ANSWER
We need to add half the coefficient of [tex]x[/tex] all square.
[tex]\frac{49}{4}[/tex]
EXPLANATION
Given the equation,
[tex]x^{2} -7x=5[/tex].
We compare to the general equation,
[tex]ax^2+bx+c=0[/tex]
This means that;
[tex]a=1,b=-7,c=-5[/tex]
To complete the square we add, [tex](\frac{b}{2})^2[/tex]
That is [tex](\frac{-7}{2})^2=\frac{49}{4}[/tex].
Hence the number to be added to both sides is [tex]\frac{49}{4}[/tex].
Note that before we complete the square, the coefficient of the term in[tex]x^2[/tex] must always be 1.
