Choice C is the correct answer. The $3y$ terms are opposites, so we add the equations.

Step 1: Add the equations: $(5x + 3y) + (5x - 3y) = 29 + 11$$10x = 40$$x = 4$

Step 2: Substitute $x = 4$ into the first equation: $5(4) + 3y = 29$$20 + 3y = 29$$3y = 9$$y = 3$

Solution: $(4, 3)$

Verification: $5(4) - 3(3) = 20 - 9 = 11$ ✓

💡 Strategic Tip: Opposite coefficients signal that addition will eliminate the variable.

Choice A is incorrect because$5(3) + 3(\frac{14}{3}) = 15 + 14 = 29$ ✓, but $5(3) - 14 = 1 \ eq 11$.

Choice B is incorrect because$5(5) - 3(\frac{4}{3}) = 25 - 4 = 21 \ eq 11$.

Choice D is incorrect because$5(2) + 3(\frac{19}{3}) = 10 + 19 = 29$ ✓, but $5(2) - 19 = -9 \ eq 11$.