5, \\
x\in D_y, y'<0, y\searrow." alt="y=4-3 \sqrt{x-5}, \\ \\ x-5 \geq 0, x \geq 5, D_y=[5;+\infty); \\ \\
y'=-\frac{3}{2 \sqrt{x-5}}; \\ \\
y'=0, -\frac{3}{2 \sqrt{x-5}}=0, \\
2 \sqrt{x-5} \neq 0, x \neq 5, \\
0\cdot x-3=0, 0\cdot x=3, x\in\varnothing; \\ \\
y'\gtrless0, -\frac{3}{2 \sqrt{x-5}}\gtrless0, \\
-\frac{3}{2 \sqrt{x-5}}<0 \ \forall x>5, \\
x\in D_y, y'<0, y\searrow." align="absmiddle" class="latex-formula">