Which of the following represents the line of symmetry of the parabola represented by the equation x2 - 10x + 21 = 0? a. x = 3 b. x = 2 c. x = 4 d. x = 5

Let us first define line of symmetry of parabola :

It is the line of symmetry of a parabola that divides a parabola into two equal halves that are reflections of each other about the line of symmetry. It intersects a parabola at its vertex. It is a vertical line with the equation of x = -b/2a.

So using the formula x=-b/2a, we can find the line of symmetry of parabola here.

We are given the equation:

If we compare it with the quadratic equation :

we get a=1, b=-10 and c=21

Now plugging the values of a and b in the formula x=-b/2a,

x=5

So the line of symmetry of given parabola is given by x=5

Option D is correct answer.

the answer is 62.8 cubic units