Increasing and Decreasing Domain of a Parabola: Representation of missing c value

Find the domain of increase of the function:

$y=-8x^2-32x$

$x < -2$

Find the domain of decrease of the function:

$y=-8x^2-32x$

$x > -2$

Find the domain of decrease of the function:

$y=4x^2-8x$

$x < 1$

Find the domain of decrease of the function:

$y=-10x^2-200x$

$x > -10$

Find the domain of decrease of the function:

$y=-30x^2-60x$

$x > -1$

Find the domain of decrease of the function:

$y=3x^2+6x$

$x < -1$

Find the domain of increase of the function:

$y=3x^2+6x$

$x > -1$

Find the domain of increase of the function:

$y=4x^2-8x$

$x > 1$

Find the domain of increase of the function:

$y=7x^2-28x$

$x > 2$

Find the domain of increase of the function:

$y=-x^2+6x$

$x < 3$

Find the domain of decrease of the function:

$y=-x^2+6x$

$x > 3$

Find the domain of decrease of the function:

$y=7x^2-28x$

$x < 2$

Find the domain of increase of the function:

$y=-4x^2+40x$

$x < 5$

Find the domain of decrease of the function:

$y=-4x^2+40x$

$x > 5$

Find the domain of decrease of the function:

$y=-3x^2+36x$

$x > 6$

Find the domain of decrease of the function:

$y=5x^2-40x$

$x < 4$

Find the domain of increase of the function:

$y=5x^2-40x$

$x > 4$

Find the domain of increase of the function:

$y=2x^2-24x$

$x > 6$

Find the domain of increase of the function:

$y=6x^2+24x$

$x > -2$

Find the domain of increase of the function:

$y=x^2+4x$

$x > -2$