Question

All of the following are equivalent, except _____.

(12 + 3)x
(12 + 3x)x
15x
12x + 3x

Answer 1

( ) in this context, preceded or followed by x, indicates required multiplication.
Try multiplying out the first two expressions before comparing the results with the second two expressions.

Answer 2

anything times 1 is itself

Answer 3

(12 + 3)x = 3x + 12x = 15x
12 + 3x)x = 3x^2 + 12x
15x = 15x
12x + 3x = 15x

So out of which of those isn't the same?

Answer 4

whats the answer to b?

Answer 5

The answer to b is 3x^2 + 12x. Thats as much as it simplifies to

Answer 6

oh ok thx