Respuesta :

Answer:

b = - 50

Step-by-step explanation:

Using F.O.I.L (First Outer Inner Last)

-5 × - 2x = 10x

-5 × 10 = - 50

10x - 50

10x - 50 = 10x + b

10x - 10x - 50 = b

b = - 50