16Hit1600
AlgebraVery hardConditions for infinitely many solutions

Algebra practice question

The system y = mx + 4 and y = 2x + b, where m and b are constants, has infinitely many solutions. Which of the following must be true?

  1. A. m = 2 and b = 4Correct
  2. B. m = 2 and b ≠ 4
  3. C. m ≠ 2
  4. D. m = 4 and b = 2

Answer: A. m = 2 and b = 4

Infinitely many solutions means the two equations describe the same line: same slope and same intercept.

Why the other answers are wrong

B. m = 2 and b ≠ 4
Same slope with different intercepts gives no solution.
C. m ≠ 2
Different slopes give exactly one solution.
D. m = 4 and b = 2
This swaps slope and intercept.

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