Q: If x + 3 = 7 - x, then x = ?
UNANSWERED.
The correct answer is B.
A: The answer is 2.
The algebra way: x + 3 = 7 - x Add x on both sides, so we can get rid of the x on the right side of the equation. 2x + 3 = 7 Subtract -3 on both sides. 2x = 4 Divide by 2 on both sides. x = 2 Remember, to double check your work by substituting your answer into the original equation. x + 3 = 7 - x 2 + 3 = 7 - 2 5 = 5 Check!!! Score points!
Or the pick and play way: The answer must be one of the multiple choice answers. Let's start with the one in the middle: C), since the SAT usually lists the answers in order from smallest to biggest. If x = 4, substitute it into the equation x + 3 = 7 - x 4 + 3 = 7 - 4 7 = 3 ?! Wrong. Maybe x needs to be smaller, so try B) x = 2. Substituting into the equation x + 3 = 7 - x 2 + 3 = 7 - 2 5 = 5 It works! So B) is the answer. No need to check the other answers, because we know B) works fine and the SAT never has more than one correct answer in the multiple choice questions.
