Question

What number must you add to complete the square x^2+xA. 1/2B. 2C. 1/4D. 1

Answer 1

for $ax^2+bx+c$

when a=1, then the value of c that will make the quadratic a perfect square (allows you to complete the square) is $(\frac{b}{2})^2$

given x^2+x

b=1

so $c=(\frac{1}{2})^2=\frac{1}{4}$

answer is C