Choice C is the correct answer. Multiply first by 3 and second by 5 to eliminate $y$.

Step 1: Multiply: $18x - 15y = 21$$20x + 15y = 125$

Step 2: Add: $38x = 146$$x = \frac{146}{38} = \frac{73}{19}$

Non-integer. - First: $6(\frac{7}{2}) - 5(4) = 21 - 20 = 1 \ eq 7$

• Second: $4(\frac{7}{2}) + 3(4) = 14 + 12 = 26 \ eq 25$

First: $6(\frac{7}{2}) - 5y = 21 - 5y$. Add: $38x = 133$$x = 3.5 = \frac{7}{2}$

Substitute: $6(\frac{7}{2}) - 5y = 1 \Rightarrow 21 - 5y = 1 \Rightarrow y = 4$

** 💡 Strategic Tip: LCM of 5 and 3 is 15.

**Other choices are incorrect based on calculation.