Final answer:
The error Tamara made when simplifying the expression 4(3x-1)=12x-1 is that she only distributed the 4 to the first term in the parentheses and forgot to distribute it to the second term.
Step-by-step explanation:
The error Tamara made when simplifying the expression 4(3x-1)=12x-1 is that she distributed the 4 only to the first term in the parentheses and neglected to distribute it to the second term. To correctly distribute the 4, she should have multiplied 4 by both terms inside the parentheses:
4(3x-1) = 4*3x - 4*1 = 12x - 4
So, the correct simplified expression is 12x - 4.