Mickey simplified the expression below. He then checked his work by substituting 4 for x. He noticed his two values were not equal. What was Mickey's error when simplifying? Expression Simplified Expression 2 x squared minus 4 x minus 9 minus x squared + 2 x + 3 x squared minus 6 x minus 6 Mickey should have added –4 and 2 when combining the coefficients of the x terms. Mickey should have added 2 and 1 when combining the x squared terms. Mickey should have added 9 and 3 when combining the constant terms. Mickey should have added –4 and –1 when combining the x terms. Mark this and return

Full question attached:

Mickey simplified the expression below. He then checked his work by substituting 4 for x. He noticed his two values were not equal. What was Mickey’s error when simplifying?

Expression: 2x^2 - 4x - 9 - x^2 + 2x + 3

Simplified expression: x^2 - 6x - 6

ANSWER CHOICES:

Mickey should have added –4 and 2 when combining the coefficients of the x terms.

Mickey should have added 2 and 1 when combining the x^2 terms.

Mickey should have added 9 and 3 when combining the constant terms.

Mickey should have added –4 and –1 when combining the x terms.

Answer

Mickey should have added –4 and 2 when combining the coefficients of the x terms.

Explanation:

To simplify an expression means to group and organize the expression in a such a way that it becomes more understandable, and can now easily be solved

Given the expression 2x² - 4x - 9 - x² + 2x + 3 to simplify

We first group and find like terms and then add and cancel out

2x²-x²- 4x+2x - 9+ 3

=x²-2x-6

Mickey did not add the coefficients -4 and +2 for x terms in the expression, instead it looked like he added 4+2 as the coefficients

Therefore the correct option is

Mickey should have added –4 and 2 when combining the coefficients of the x terms.

Mickey should have added –4 and 2 when combining the coefficients of the x terms.

Step-by-step explanation: