y=-(x-a)(x-b)

Solution for y=-(x-a)(x-b) equation:

Simplifying
y = -1(x + -1a)(x + -1b)

Reorder the terms:
y = -1(-1a + x)(x + -1b)

Reorder the terms:
y = -1(-1a + x)(-1b + x)

Multiply (-1a + x) * (-1b + x)
y = -1(-1a * (-1b + x) + x(-1b + x))
y = -1((-1b * -1a + x * -1a) + x(-1b + x))
y = -1((1ab + -1ax) + x(-1b + x))
y = -1(1ab + -1ax + (-1b * x + x * x))
y = -1(1ab + -1ax + (-1bx + x2))
y = -1(1ab + -1ax + -1bx + x2)
y = (1ab * -1 + -1ax * -1 + -1bx * -1 + x2 * -1)
y = (-1ab + 1ax + 1bx + -1x2)

Solving
y = -1ab + 1ax + 1bx + -1x2

Solving for variable 'y'.

Move all terms containing y to the left, all other terms to the right.

Simplifying
y = -1ab + 1ax + 1bx + -1x2