Area of a square = Side × Side
Side = 7x-3
Area of the square = (7x-3) × (7x-3)
= 7x(7x-3) -3(7x-3)
= 49x^2 -21x -21x +9
=49x^2 -42x +9
Given:
The equations of parabolas in the options.
To find:
The steepest parabola.
Solution:
We know that, if a parabola is defined as

Then, the greater absolute value of n, the steeper the parabola.
It can be written as


where
, the smaller absolute value of p, the steeper the parabola.
Now, find the value of |p| for eac equation
For option A, 
For option B, 
For option C, 
For option D, 
Since, the equation is option A has smallest value of |p|, therefore, the equation
represents the steepest parabola.
Hence, the correct option is A.
Answer:
d(-8)=-8 . it is very easy