The distributive states that a(b + c) = ab + ac.
The distributive property is useful of simplifying parentheses.
Example:
3(x - 1) + 5 = 20
3(x - 1) expression can be simplified with the distributive property.
3(x - 1) + 5 = 20
3x - 3 + 5 = 20
After this you would combine any like terms and solve for x.
There can be also more than two terms in the parentheses:
a(b + c + d) = ab + ac + ad.