2
algebra

For what values of kk does the system have no solution? {y=4x3y=kx+5\begin{cases} y = 4x - 3 \\ y = kx + 5 \end{cases}

A

k=3k = -3

B

k=5k = 5

C

k=4k = 4

D

k=4k = -4

Correct Answer: C

Choice C is the correct answer. For no solution, we need parallel lines.

Analysis:

  • First line: slope = 4, y-intercept = -3
  • Second line: slope = kk, y-intercept = 5

Condition for parallel lines (no solution):

  • Same slope: k=4k = 4
  • Different y-intercepts: 3 eq5-3 \ eq 5 ✓ (already different)

With k=4k = 4, the lines are parallel and never intersect.

💡 Strategic Tip: In slope-intercept form, equal slopes with different intercepts = no solution.

Choice A is incorrect because k=3k = -3 means different slopes (4 and -3), giving one solution.

Choice B is incorrect because k=5k = 5 means different slopes, giving one solution.

Choice D is incorrect because k=4k = -4 means different slopes, giving one solution.