Which of the following equations have no solutions? choose all answers that apply: choose all answers that apply: (choice a) a -40x+40=20x+20−40x+40=20x+20minus, 40, x, plus, 40, equals, 20, x, plus, 20 (choice b) b 20x+40=40x+2020x+40=40x+2020, x, plus, 40, equals, 40, x, plus, 20 (choice c) c -20x+40=-20x+20−20x+40=−20x+20minus , 20, x, plus, 40, equals, minus, 20, x, plus, 20 (choice d) d 40x+40=40x+2040x+40=40x+20