Find the domain in y=sqrt(4-x)y=4x?

1 Answer
Mar 19, 2018

x<=4x4 or (-oo,4](,4]

Explanation:

Since this is a square root, the values inside cannot be lesser that 0. Else, you would end up with an imaginary number. So, with that information, we can write the inequality:

4-x>=04x0

Solve for xx:

=> -x>=0-4x04

=>-x>=-4x4

Now, when we multiply both sides by a negative, we have to switch the signs:

(-1)-x<=(-1)-4(1)x(1)4

x<=4x4

We can also represent this as:

(-oo,4](,4]

And there we have our answer.