Question 233447
*[invoke describe_linear_equation 4, 2, 8 ]*[invoke linear_substitution "x", "y", 1, 1, 2, 1, -1, 0 ]*[invoke substitution "x^2-2x", "x", 3 ]*[invoke substitution "x^2-2x", "x", 3 ]*[invoke linear_equation "x", 2, 1, 5 ]