The domain of a function is the set of all the x terms of the function and the range of a function is the set of all the y terms of a function.
For example, take a look below.
The domain is the set of all x terms in each ordered pair and the
range will be the set of all the y terms in each ordered pair.
Let G be some point on the diagonal line away from point E.
Angle DEG represents angle 1.
We're given that angle DEF is a right angle which means it's 90 degrees. Angle DEG is some angle smaller than 90 degrees. By definition, that must mean angle 1 is acute. Any acute angle is smaller than 90 degrees. There's not much else to say other than this is just a definition problem.
----------------
Extra side notes:
If angle 1 was a right angle, then that would mean angle GEF would have to be 0 degrees; however the diagram shows this isn't the case.
If angle 1 was obtuse, then there's no way we'd be able to fit it into angle DEF. In other words, there's no way to have an angle larger than 90 fit in a 90 degree angle.
Answer:

Step-by-step explanation:
The formula for the length of a vector/line in your case.
![L = \sqrt{(x_2-x_1)^2 + (y_2-y_1)^2} = \sqrt{[4 - (-1)]^2 + [2 -(-3)]^2} = \sqrt{5^2 + 5^2} = \sqrt{50} = 5\sqrt{2}](https://tex.z-dn.net/?f=L%20%3D%20%5Csqrt%7B%28x_2-x_1%29%5E2%20%2B%20%28y_2-y_1%29%5E2%7D%20%3D%20%5Csqrt%7B%5B4%20-%20%28-1%29%5D%5E2%20%2B%20%5B2%20-%28-3%29%5D%5E2%7D%20%3D%20%5Csqrt%7B5%5E2%20%2B%205%5E2%7D%20%3D%20%5Csqrt%7B50%7D%20%3D%205%5Csqrt%7B2%7D)
First make and equation. Since you want to find the number of the day where both charge the same total amount, you would make the equation:
let x= the number of days
110+46(x)=70+54(x)
Solve:
110-70+46(x)=70-70+54(x)
40+46(x)=54(x)
40+46(x)-46(x)=54(x)-46(x)
40=8(x)
40/8=8x/8
5=x
Therefore your answer would be 5 days