Question

The problem is in the picture :)

Answer 1

Answer:

Last option: 4

Step-by-step explanation:

The quadratic equation simplified: $x^2-4x=-\frac{7}{2}$ has the form:

$ax^2+bx=c$

In this case, you can identify that "a", "b" and "c" are:

$a=1\\b=-4\\c=-\frac{7}{2}$

To solve this quadratic equation  by completing the square, Carlos should add $(\frac{b}{2})^2$ to both sides of the equation. This is:

$(\frac{-4}{2})^2=(-2)^2=4$

Then:

$x^2-4x+4=-\frac{7}{2}+4$

Therefore you can observe that the number he should add to both sides of the equation is: 4