# What is a better way to do this? x(x+2)-x^2-2x I opened the brackets but i don't know if it is best to start this way?

sciencesolve | Teacher | (Level 3) Educator Emeritus

Posted on

You may also consider the terms -`x^2 - 2x` where you can factor out -`x` , such that:

`-x(x + 2)`

Substituting back in expression -`x(x + 2)` for -`x^2 - 2x` yields:

`x(x + 2) - x(x + 2)`

Factoring out `(x+2)` yields:

`x(x + 2) - x(x + 2) = (x+2)(x - x)`

`x(x + 2) - x(x + 2) = (x+2)*0`

`x(x + 2) - x(x + 2) = 0`

Hence, evaluating the expression `x(x + 2) - x^2 - 2x` yields `x(x + 2) - x^2 - 2x = 0.`

giorgiana1976 | College Teacher | (Level 3) Valedictorian

Posted on

The most common way to solve the given example is to open the brackets first. But it is not the only way to solve it.

For instance, in this case, we can factorize the expression by x:

x(x + 2 - x - 2)

We'll eliminate like terms inside the brackets and we'll get:

x*0 = 0

If we'll go classical, we'll oent the brackets using the distributivity of multiplication over addition:

x^2 + 2x - x^2  - 2x = 0

We'll combine and eliminate like terms and we'll get zero.