8. A) X + − 23 = + 17 ⇔ + X 23 17 = ⇔ X = − 6

Question

2.8. a)  x + − 23 = + 17 ⇔ + x 23 17 = ⇔ x = − 6 : vô nghi ệm. b) − 5 . x = − 20 ⇔ 5. x = 20 ⇔ x = ⇔ = ± 4 x 4 .

Answer

2.8. a)  x + − 23 = + 17 ⇔ + x 23 17 = ⇔ x = − 6 : vô nghi ệm. b) − 5 . x = − 20 ⇔ 5. x = 20 ⇔ x = ⇔ = ± 4 x 4 .