For the function $y=(x-7)(x+5)(4 x-3)$, its $y$-intercept is $y=$ its $x$-intercepts are $x=$ Note: If there is more than one answer enter them separated by commas. If there are none, enter none . When $x \rightarrow \infty, y \rightarrow \square \infty$ (Input + or - for the answer ) When $x \rightarrow-\infty, y \rightarrow \infty($ Input + or - for the answer $)$

Step 1 ：The $y$-intercept of a function is the point where the function crosses the $y$-axis. This occurs when $x=0$. So, we substitute $x=0$ into the function $y=(x-7)(x+5)(4x-3)$ to find the $y$-intercept.

Step 2 ：Substituting $x=0$ into the function gives $y=(-7)(5)(-3)=105$.

Step 3 ：The $x$-intercepts of a function are the points where the function crosses the $x$-axis. This occurs when $y=0$. So, we set the function $y=(x-7)(x+5)(4x-3)$ equal to $0$ and solve for $x$ to find the $x$-intercepts.

Step 4 ：Setting the function equal to $0$ gives $(x-7)(x+5)(4x-3)=0$. This equation is satisfied when $x=7$, $x=-5$, or $x=\frac{3}{4}$.

Step 5 ：As $x$ approaches infinity, the term $4x-3$ dominates the function. Since the coefficient of $x$ in this term is positive, the function approaches positive infinity. So, when $x \rightarrow \infty, y \rightarrow +\infty$.

Step 6 ：As $x$ approaches negative infinity, the term $x+5$ dominates the function. Since the coefficient of $x$ in this term is positive, the function approaches negative infinity. So, when $x \rightarrow -\infty, y \rightarrow -\infty$.

Step 7 ：So, the $y$-intercept is $y=\boxed{105}$, the $x$-intercepts are $x=\boxed{7, -5, \frac{3}{4}}$, when $x \rightarrow \infty, y \rightarrow \boxed{+\infty}$, and when $x \rightarrow -\infty, y \rightarrow \boxed{-\infty}$.