Question

Why is subtracting an expression similar to distributing a –1? Use the drop-down menus to explain your answer.

Answer 1

Answer:

When subtracting expressions, we are applying the distributive property, where a multiple of an expression in brackets is applied to to each term.

e.g.

a(x + y) = ax + ay

In the case of subtracting an expression, we're doing the same thing, but in the example above, "a" would be equal to -1.

(a + b) - (c + d) ≡ (a + b) + -1(c + d)

And so the negative one is distributed across the terms within the brackets.