Q: 4x - 7 = 9. Solve for x.
UNANSWERED.
The correct answer is D.
A: The answer is 4.
The algebra way: 4x - 7 = 9 4x = 16 x = 16 / 4 = 4 Remember, to double check your work by substituting your answer into the original equation. 4*4 - 7 = 9 16 - 7 = 9 Great!
Or the plug and play way: The answer must be one of the multiple choice answers. Try the answer in the middle (i.e. C) first, since the SAT usually lists the answers in order from smallest to biggest. If x = 3, substitute it into the equation 4x - 7 = 9. 12 - 7 = 9 5 = 9 Nope. Let's try answer B). Substitute x =2 into 4x - 7 = 9. 8 - 7 = 9 1 = 9 Opps, we're getting farther away from what we want. Since we just tried a smaller number, lets go the opposite way and try a bigger number. Let's try answer D) . Substitute x = 4 into 4x - 7 = 9. 16 - 7 = 9. Got it! Good going!!!
