Question

Marco states that both expressions are equal to x. Do you agree or disagree with Marco? Explain your thinking. 8x-7x -5x+5x

Answer 1

We diagree with Marco because

`8x-7x=x`

and

`-5x+5x=0`

where, in the first expression, we factorized x and got

`8x-7x=(8-7)x=1x=x`

and in the second one, we got

`(-5+5)x=0\cdot x=0`

In summary, the first expression is equal to x and the second one is equal to zero, so they are different expressions.