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


x = -4

x = -2

x = 2

Verified Answer :

it would be the last one, x=2

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

Step-by-step 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:

\(x=-\dfrac{b}{2a}.\)

From equation (i), we have

a = - 3,  b = 12  and  c = -11.

Therefore, the line of symmetry for the given equation is

\(x=-\dfrac{b}{2a}\\\\\\\Rightarrow x=-\dfrac{12}{2\times (-3)}\\\\\\\Rightarrow x=\dfrac{12}{6}\\\\\\\Rightarrow x=2.\)

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

Option (C) is correct.