1a.
10, x\in(10;+\infty), y'>0, y\nearrow; \\ x_{min}=10, y_{min}=-57; \\" alt="y=(8x+1) ^{ \frac{5}{4} } -30x, \\
8x+1 \geq 0, x \geq - \frac{1}{8}, D_y=[- \frac{1}{8};+\infty);\\
y'=((8x+1) ^{ \frac{5}{4} } -30x)'=10(8x+1) ^{ \frac{1}{4} } -30, \\
y'=0, \frac{5}{4}(8x+1) ^{ \frac{1}{4} } -30=0, \\
(8x+1) ^{ \frac{1}{4} }=3, \\
8x+1=3^4, \\
x=10;
y'\gtrless0, \\
x<10, x\in[- \frac{1}{8};10), y'<0, y\searrow; \\
x>10, x\in(10;+\infty), y'>0, y\nearrow; \\ x_{min}=10, y_{min}=-57; \\" align="absmiddle" class="latex-formula">
1б.
2.