expansion ExpandRule1a:
	-1 * (a + b) -> -1*a - b
expansion ExpandRule1b:
	-1 * (a - b) -> -1*a + b
expansion ExpandRule1c:
	-1 * (a +- b) -> [-1*a + b, -1*a - b]
expansion ExpandRule1d:
	x - (a + b) -> x + (-1*a - b)
expansion ExpandRule1e:
	x +- (a + b) -> [x + (a + b), x + (-1*a - b)]
expansion ExpandRule1f:
	x - (a - b) -> x + (-1*a + b)
expansion ExpandRule1g:
	x +- (a - b) -> [x + (a - b), x + (-1*a + b)]
expansion ExpandRule1h:
	x - (a +- b) -> [x + (-1*a + b), x + (-1*a - b)]
expansion ExpandRule1i:
	x +- (a +- b) -> [
		x + (a + b),
		x + (a - b),
		x + (-1*a + b),
		x + (-1*a - b),
	]

expansion ExpandRule2a:
	a * (b + c) -> a*b + a*c
expansion ExpandRule2b:
	(b + c) * a -> a*b + a*c

expansion ExpandRule5a:
	-(-a) -> a
expansion ExpandRule5b:
	-1 * (-1 * a) -> a