Tyler is simplifying the expression 6−2x+5+4x . Here is his work: 6−2x+5+4x (6−2)x+(5+4)x 4x+9x 13x a. Tyler’s work is incorrect. Explain the error he made. Input Field 1 of 2

Question

Tyler is simplifying the expression 6−2x+5+4x .

Here is his work:

6−2x+5+4x

(6−2)x+(5+4)x

4x+9x

13x

Tyler’s work is incorrect. Explain the error he made.

Answer 1

(6-2)x + (5-4)x does = 13x

If there were parentheses as in the 2nd line, everything else is correct

the mistake is going from

6-2x + 5-4x to

(6-2x) + (5-4)x

PEMDAS is the order of operations. P for parentheses 1st, Multiplication 3rd, addition 4th, subtraction 5th

(there are no exponents or division or parentheses, so it's just M, A and S that apply)

combine like terms, 2x-4x =-2x

combine the constant terms 6+5 = 11

6-2x +5-4x = 11-2x

The mistake was assuming parentheses when they aren't there.

correct answer is 11-2x not 13x