10 (1+3b) + 15b = - 20

Distributive property

Solve for X

b = - 2/3

Step-by-step explanation:

Assuming we are solving for b

10 (1+3b) + 15b = - 20

Distribute

10+30b + 15b = - 20

Combine like terms

10 + 45b = - 20

Subtract 10 from each side

10-10 + 45b = - 20-10

45b = - 30

Divide by 45

45b/45 = - 30/45

b = - 2/3