16Hit1600
AlgebraEasyEquation whose solution is zero

Algebra practice question

For which value of x is the expression 4x + 9 equal to 9?

  1. A. 0Correct
  2. B. 9/4
  3. C. −9/4
  4. D. 1

Answer: A. 0

Subtract 9 from both sides: 4x = 0. Divide by 4: x = 0. Check: 4(0) + 9 = 9.

Why the other answers are wrong

B. 9/4
9/4 comes from 4x = 9, forgetting to subtract the 9 that is already on the left side.
C. −9/4
−9/4 comes from moving the 9 over but dropping the 9 on the right: 4x = −9. Both 9s are there, and they cancel.
D. 1
4(1) + 9 = 13, not 9.

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