Question

Question #d4f12

Answer 1

`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`