The line of symmetry for the quadratic equation y=ax^2-2x-3 is x=1. What is the value of "a"?

a = 1.

Step-by-step explanation:

For the general vertex form:

y = a (x - b) ^2 + c the line of symmetry is x = b.

y = ax^2 - 2x - 3

y = a (x^2 - 2x/a) - 3

y = a[ (x - 1/a) ^2 - (1/a) ^2] - 3

y = a (x - 1/a) ^2 - 1/a - 3

Here the line of symmetry is x = 1 so we have:

1/a = 1

a = 1.