transformation = Transformation(MultiplyBy(5), Add(10))
transformed_4 = transformation(4)

restored_4 = transformation.restore(transformed_4)
assert restored_4 == 4 # не будем учитывать пока ошибки округления

from sympy import symbols, solve, simplify, factor
from sympy.parsing.sympy_parser import (
  parse_expr,
  standard_transformations,
  implicit_multiplication,
  implicit_multiplication_application)

trf = (
  standard_transformations +
  (implicit_multiplication_application,))

x, y, z, t = symbols('x y z t')

formula_str = "5*x + 10"
formula = parse_expr(formula_str, transformations=trf)
print(formula)
#5*x + 10

res = formula.subs(x, 4)
print(res)
#30

# решение уравнения: `5*x + 10 = 0`
print(solve(formula))
#[-2]

# решение уравнения: `5*x + 10 = 30` или `5*x + 10 - 30 = 0`
print(solve(formula_str + f" - {res}"))
#[4]

In [94]: [r for r in solve('x**4-(x-2)**2') if r.is_real]
Out[94]: [-2, 1]

In [95]: simplify('sin(x)**2 + cos(x)**2')
Out[95]: 1

In [96]: factor('x**4-(x-2)**2')
Out[96]: (x - 1)*(x + 2)*(x**2 - x + 2)

In [100]: simplify('sin(x)**2 / (1 - sin(x)**2)')
Out[100]: tan(x)**2

class Transform():
    def __init__(self,x=0,mul=1,add=0):
        self.x = x
        self.mul = mul
        self.add = add
    def calculate (self):
        self.res = self.x*self.mul + self.add
        return self.res
    def reverse (self):
        self.reverse = (self.res-self.add)/self.mul
        return self.reverse
    def expose (self):
        return "{}x{}+{}".format(self.x, self.mul, self.add)

eq1 = Transform(5, 2, 20)
print(eq1.calculate())
print(eq1.expose())
print(eq1.reverse())

30
5x2+20
5.0