Problem 30 of 35alg-030
Which of the following expressions is equivalent to ?
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Solution walkthrough1:32
- The minus sign in front of the second bracket subtracts every term inside it, not only the first.
- Subtracting a term is the same as adding its opposite. Flip every sign: .
- Add like terms, column by column: and .
- The plain numbers: . The result is .
- Traps: flipping only the first sign, flipping two signs but not the third, or adding instead of subtracting.