Luka, Zara, and Kim simplified the following expression: -3(x+4) – 2(5x – 6). Their work is shown below. Who simplified the expression correctly? Explain your answer. (Hint:
None, one, or two of the students could be correct.)
I
Luka
-3(x+4) - 2(5x-6)
-3(x+4) + -2(5x + -6)
-3x + -12 + -10x + 12
-13x
Zara
-3(x+4) - 2(5x-6)
-3x + -12 - (10x -12)
-3x + -12 - 10x + 12
-13x
Kim
-3(x+4) - 2(5x - 6)
-3x + -12 - 10x - 12
-13x - 24