Distributing a Minus

When the number outside is negative, its sign is multiplied into every term too. -2(x - 5): -2 times x is -2x, and -2 times -5 is +10, because a negative times a negative is positive. So the result is -2x + 10.

A minus sign alone in front of parentheses is a hidden -1. -(x + 3) means -1 × (x + 3), which is -x - 3. Every sign inside flips: the plus in front of 3 becomes a minus.

The usual slip is to change only the first sign and write -2x - 10. Treat each term inside as a signed number, multiply it by the outside number, and use the sign rules from Section 1 every time.