Question

Kelly wrote the following steps to prove the equation:

Given: 2(x – 3) = 5x + 3
Prove: x = –3
Which step of justification is incorrect, and what should the justification for that step be to solve the equation?

Answer 1

Step 4; Combine Like Terms
Step 1; Commutative Property of Multiplication
Step 2; Associative Property of Addition
Step 3; Symmetric Property of Equality

Answer 2

Symmetric property of equality states that if a=b then b=a, and all it really did in step 3 was flip things around nothing more. Transitive property states if a=b and b=c then a=c. So step 3 would be incorrect. Do you understand that? Or do you want a better explanation :)?

Answer 3

Simple 2x-6=5x+3
-9=3x
-3=x
therefore x=-3

Answer 4

That's true but the question was asking which justification in the proof was incorrect i think.

Answer 5

Yes i understand that was actually what I got. So it's the last one right?

Answer 6

Yup that's it :)

Answer 7

Thank you

Answer 8

No problem :D