Question

What is the line of symmetry for the graph of y = -3x2 + 12x - 11?

x = -4
x = -2
x = 2

Answer 1

it would be the last one, x=2

Answer 2

Answer: The correct option is (C) x = 2.

Explanation: We are given to select the correct option that gives the line of symmetry for the graph of the following equation:

`y=-3x^2+12x-11~~~~~~~~~~~~~~~~~~~~~~~~~~(i)`

We know that the graph of a quadratic equation in the form

`y=ax^2+bx+c` has as its line of symmetry given by:

`x=-(b)/(2a).`

From equation (i), we have

a = - 3, b = 12 and c = -11.

Therefore, the line of symmetry for the given equation is

`x=-(b)/(2a)\\\\\\\Rightarrow x=-(12)/(2* (-3))\\\\\\\Rightarrow x=(12)/(6)\\\\\\\Rightarrow x=2.`

Thus, the required line of symmetry is x = 2.

Option (C) is correct.