Question #d4f12

1 Answer
Nov 14, 2017

49/4

Explanation:

To make a complete square, we can make a square of (ax+b)^2.

(ax+b)^2
=a^2x^2+2abx+b^2

In x^2-7x,
a^2=1 and 2ab=-7
Therefore a=1, b=-7/2 or a=-1, b=7/2

Hence, the required value
=b^2
=(-7/2)^2 or (7/2)^2
=49/4