Question

All of the following expressions are equivalent except _____.

7 - x
x - 7
- x + 7
7 + (- x)
I think c

Answer 1

All of the following expressions are equivalent except x-7

Explanation:

Two expressions are said to be equivalent if by some arrangement of terms they are equal to each other.

Now by looking at the four given choices we have:

1)

7-x

2)

x-7

3)

-x+7

which is nothing but:

7-x

4)

7+(-x)

which on opening the parentheses term:

7-x

Hence, we get that 1) , 3) and 4) expressions are same i.e. they are equivalent.

whereas the expression which is different is: x-7

Answer 2

well,
7 - x is the same as -x + 7. You find this by doing the Keep - Change - Change method.

7 + -x is equivalent to -x + 7 so this answer (choice #4) is okay.

x - 7 is the same as x + -7 which is different than all the others (so choice #2 is something to consider)

and -x + 7 is the same as all answer choices except for choice #2, which is x + -7.

So basically the only uncommon answer is answer choice #2. x - 7

CHOICE #2 is your answer :)