Question

How do you find the domain and range of `sqrt (4-5x)`?

Answer 1

I found:

`-oo<` `x` `<=4/5`
`0<=y` `<+oo`

Explanation:

The domain is found setting the argument of the square root bigger or equal to zero (to avoid a negative root):
`4-5x>=0`
so that must be: `x<=4/5`
The domain will be all the `x` from `-oo` up to and comprising `4/5`.

The range will be all the `y` that go from zero (when `x=4/5`) up to `+oo`.

Graphically:

graph{sqrt(4-5x) [-10, 10, -5, 5]}