Choice D is the correct answer. For exactly one solution, the lines must intersect at a single point, which means they must have different slopes.

Analysis:

• First line has slope = 3
• Second line has slope = $m$

Condition for one solution: $m \ eq 3$

Why:

• If $m = 3$: both lines have slope 3 but different y-intercepts (5 and -2), making them parallel → no solution
• If $m \ eq 3$: lines have different slopes → they intersect at exactly one point

💡 Strategic Tip: Different slopes guarantee exactly one solution.

Choice A is incorrect because while $m = 5$ gives one solution, it's not the only value that works.

Choice B is incorrect because while $m = -2$ gives one solution, it's not the only value that works.

Choice C is incorrect because$m = 3$ gives no solution (parallel lines), not one solution.