Answer:
[tex]\large\boxed{\sf \ \ 49 \ \ }[/tex]
Step-by-step explanation:
Hello,
we need to get the discriminant = 0 meaning
[tex]\Delta = b^2-4ac = 0\\\\<=>14^2-4c=0\\\\<=>c=\dfrac{196}{4}=49[/tex]
And then the square is
[tex]x^2-2\cdot 7\cdot x+7^2=(x-7)^2[/tex]
Hope this helps
