Question

A student is attempting to simplify the express below. Sample mathematical work is shows. which statement best applies to the sample mathematical work?
Given a+b-2(ab-a), I first apply the distributive property, which yields the expression a+b-2ab+2a. I can then collect like terms: since a+2a=3a, I have the expression 3a+b-2ab as my final answer

a) the student failed to properly apply the distributive property
b) the student collected two or more terms that were not like terms
c) the student failed to collect all like terms
d) the mathematical work shown above is correct

Answer 1

The answer is d) the mathematical work shown above is correctproof

a+b-2(ab-a) = a+b-2ab+2a = 3a+b-2ab

Answer 2

Answer:

D- The mathematical work shown above is correct

Step-by-step explanation:

Given $a+b-2(ab-a)$,

Applying distributive property we get, $a+b-2ab+2a$

Now collecting the like terms we get, $3a+b-2ab$ as $a+2a=3a$

Now, we can see that the answer is correct and the student also did the right steps to get the answer.  

$a+b-2(ab-a)=a+b-2ab+2a$ = $3a+b-2ab$

Therefore, option D is correct.