import sympy as sym

# Defining symbols:

x, a, b = sym.symbols('x, a, b')

# Defining an expression:

E1 = sym.sqrt(2)*a*x**2 + b*x

# Solving E1 = 0 for x, and denoting the result E2:

E2 = sym.solve(E1, x)
print('E2 =', E2)

# Calc numeric value of solution E2[1] with lambdify():

fun_E2_1 = sym.lambdify([a, b], E2[1], 'numpy')
val_E2_1 = fun_E2_1(a=1, b=2)
print('val_E2_1 =', val_E2_1)