find the domain for the rational function
1. (−∞, 1) (1, ∞)

2. (−∞, −1) (−1, ∞)

3. (−∞, 3) (3, ∞)

4. (−∞, −3) (−3, ∞)

step-by-step explanation:

your answer   is c

step-by-step explanation:

let x and 400 - x be the two numbers.  

==> 0.80x + 0.85(400 - x) = 400 - 68 from the statement of the problem.  

< ==> 0.80x + 0.85(400 - x) = 400 - 68  

==> 340 - 0.05x = 332  

< ==> -0.05x = -8 ==> x = 160, the first number ==> 400 - x = 240, the second number.