SAT Math Question of the Day

Math Category: Roots Level 2:

Q: -2 √ 3  + 4 √ 3  + 7 √ 5  - 3 √ 5

  1. 2 √ 3  + √ 5
  2. √ 3  + 2 √ 5
  3. 2 √ 3  + 4 √ 5
  4. 4 √ 3  + 3 √ 5
  5. 5 √ 3  + 4 √ 5

UNANSWERED.

The correct answer is C.

A: The answer is 2 √ 3  + 4 √ 5.

Add like terms: -2 √ 3  + 4 √ 3 is 2 √ 3.
7 √ 5 - 3 √ 5 is 4 √ 5 .
Another way to imagine it is to replace √ 3 with an Orange and √ 5 with a Banana.
4 Oranges - 2 Oranges = 2 Oranges, so that's 2 √ 3 .
7 Bananas - 3 Bananas = 4 Bananas, so that's 4 √ 5 .