Question 118·Easy·Equivalent Expressions
Which expression is equivalent to ?
For expression-equivalence questions with parentheses and negative signs, first distribute any coefficients or minus signs outside the parentheses to every term inside. Then rewrite the expression without parentheses and systematically combine like terms (group terms, terms, and constants). If unsure, you can quickly check your result by plugging in a simple number like or into both the original expression and your simplified expression to see if the values match.
Hints
Handle the minus sign first
Focus on the expression . How does a negative sign in front of parentheses affect each term inside?
Rewrite before combining
After you distribute the negative sign, rewrite the full expression without the first set of parentheses. Then remove the second set of parentheses as well.
Group like terms carefully
Once all parentheses are gone, group together the terms, the terms, and the constant terms, and then combine their coefficients.
Desmos Guide
Enter the original expression
Type the original expression as y = -(2x^2 - 3x + 5) + (x^2 + 4x - 1) so Desmos will graph it or generate a table of values.
Compare with each answer choice
On new lines, enter y = x^2 + 7x - 6, y = -x^2 - 7x + 6, y = -3x^2 + x - 4, and y = -x^2 + 7x - 6. Use the graph or a table to see which choice produces the same -values as the original expression for many different -values—that expression is equivalent to the original.
Step-by-step Explanation
Distribute the negative sign
Start with the expression:
The minus sign in front of the first parentheses means you multiply each term inside by :
So the whole expression becomes:
Remove the remaining parentheses
Now drop the parentheses around the second expression (because nothing is in front of it to change the signs):
Group like terms
Group the terms by powers of and constants:
- terms: and
- terms: and
- Constant terms: and
Combine coefficients to get the final expression
Combine each group:
- For :
- For :
- For constants:
So the simplified expression is
This matches choice D.