Question

Can someone help me answer these two questions? I wanna know what's right and wrong. Please correct me if Necessary

Answer 1

Remember that the general equation of a line is $y=mx+b$, where:
$m$ is the slope, and $b$ is the y-intercept; so to find the y-intercept, solve for $y$ and identify $b$.
Now, to find the x-intercept, just replace $y$ in your line equation with $0$, and solve for $x$
Lets apply those procedures to our two questions:

1. - y-intercept:
$-10x+5y=40$
$5y=10x+40$
$y= \frac{10x+40}{5}$
$y=2x+8$
Notice that now we have our line equation in the form $y=mx+b$ with $m=2$ and $b=8$; sine $b$ is the y-intercept, we can conclude that the y-intercept of our equation is 8.

x-intercept:
First, lets replace $y$ with $0$:
$0=2x+8$
And then, we can solve for $x$ to find our x-intercept:
$2x=-8$
$x= \frac{-8}{2}$
$x=-4$
We can conclude that our x-intercept is -4; thus the correct answer in your list is the fourth one: x-intercept is -4; y-intercept is 8.

2. y-intercept:
$5x+4y=80$
$4y=-5x+80$
$y= \frac{-5x+80}{4}$
$y=- \frac{5}{4} x+20$
We can conclude that our y-intercept is 20.

x-intercept:
$0=- \frac{5}{4} x+20$
$- \frac{5}{4} x=-20$
$x=( \frac{4}{5} )(20)$
$x=16$
We can conclude that our x-intercept is 16; thus the correct answer in your list is, once again, the fourth one: x-intercept is 16; y-intercept is 20.