### Instruction: A line is described by the equation $y-4=4(x-8)$. What is the sum of its $x$-intercept and $y$-intercept?### Response: I know that the $x$-intercept is the value of $x$ when $y=0$, and the $y$-intercept is the value of $y$ when $x=0$.
To find the $x$-intercept, I can plug in $y=0$ into the equation and solve for $x$.
So I get $0-4=4(x-8)$, which simplifies to $-4=4x-32$, and then to $4x=28$, and then to $x=7$.
So the $x$-intercept is 7.
To find the $y$-intercept, I can plug in $x=0$ into the equation and solve for $y$.
So I get $y-4=4(0-8)$, which simplifies to $y-4=-32$, and then to $y=-28$.
So the $y$-intercept is -28.
To find the sum of the $x$-intercept and the $y$-intercept, I just need to add 7 and -28.
So I get 7 + (-28) = -21.