30 Test file number 42

  30.1 Problem number 20
  30.2 Problem number 21
  30.3 Problem number 64

Test folder name:

test_cases/1_Algebraic_functions/1.2_Trinomial_products/1.2.2_Quartic/42_1.2.2.5_P-x-a+b_x^2+c_x^4-^p