Answer: Sergio's expression is incorrect because he can not simplify 3-6x and Leon's expression is incorrect because he did not multiply 3 by -1.
Step-by-step explanation:
Here, given expression, 9 - (3 - 6x)
After simplifying this we get the following steps,
Step 1) 9 - (3 - 6x) = 9 - 3 +6x ( by removing parenthesis ) -----(1)
Step 2) 9 - (3 - 6x) = 6 + 6x
Step 3) 9 - (3 - 6x) = 6(1 + x) ( because 6 is common in both term of right side)
Since, when Sergio simplified it he wrote 9−(-3x), which is not matching to the above steps. that, is he is incorrect, because in his explanation he wrote -3x after simplifying 3-6x which can not be solved.
Moreover, the expression of Leon is also not matching to any of the above steps,
Thus he is also incorrect because after removing parenthesis he did not multiply 3 by -1 .
