Помогите решить задачу

Иииb $\left \{ {{2^{x}\cdot 4^{y}=16} \atop {5^{3x}-5^{4y+7}=0}} \right. \; \left \{ {{2^{x}\cdot 2^{2y}=2^4} \atop {5^{3x}=5^{4y+7}}} \right. \; \left \{ {{2^{x+2y}=2^4} \atop {5^{3x}=5^{4y+7}}} \right. \; \left \{ {{x+2y=4} \atop {5^{3x}=5^{4y+7}}} \right. \\\\\\ \left \{ {{x=4-2y} \atop {5^{3(4-2y)}=5^{4y+7}}} \right. \; \left \{ {{x=4-2y} \atop {12-6y=4y+7}} \right. \; \left \{ {{x=4-2y} \atop {10y=5}} \right. \; \left \{ {{x=4-2\cdot \frac{1}{2}=3} \atop {y=\frac{1}{2}}} \right.$

$Otvet:\; (3,\frac{1}{2})$