SAT Math Question of the Day

Math Category: Roots Level 2:

Q: 8 √ 5  - 4 √ 2  + 3 √ 2  + 2 √ 5

  1. 2 √ 2  + √ 5
  2. 4 √ 2  + 3 √ 5
  3. 5 √ 2  + 4 √ 5
  4. 10 √ 5  - √ 2
  5. 9 √ 2  + 6 √ 5

UNANSWERED.

The correct answer is D.

A: The answer is 10 √ 5  - √ 2 .

Add like terms: 3 √ 2  - 4 √ 2 is - √ 2 .
8 √ 5  + 2 √ 5 is 10 √ 5 .
Another way to imagine it is to replace √ 2 with an Apple and √ 5 with a Banana.
3 Apples - 4 Apples = - Apples, so that's - √ 2 .
8 Bananas + 2 Bananas = 10 Bananas, so that's 10 √ 5 .