We look at linear expressions that have parentheses, focusing on those where a quantity is multiplied by a negative number, or just has a negative sign in front, such as: 14x − 9(3x − 5) or 7s + 2 − (−10 − 6s).
You just have to be careful with the signs, when using the distributive property with these.
When there is just a minus sign, you can imagine a one in front of the quantity in parentheses. As a shortcut, the sign of each term inside parentheses changes to the opposite, in that situation. As an example, 7s + 2 − (−10 − 6s) simplifies first to 7s + 2 + 10 + 6s.
Then we also solve an equation where this new skill is useful.
Word problems — video lesson
Math Mammoth Grade 8 curriculum