# Math homework help; Models of Rational Function?

Can you guys help me with this;-; as much better can you also give me a brief explanation about whats happening here? Direction: Write the rational function model for each problem. 1. The denominator of a fraction is 2 less than twice the numerator. If 7 is added to both the numerator and the denominator, the... show more Can you guys help me with this;-; as much better can you also give me a brief explanation about whats happening here?

Direction: Write the rational function model for each problem.

1. The denominator of a fraction is 2 less than twice the numerator. If 7 is added to both the numerator and the denominator, the resulting fraction is 4/5. Write the original fraction.

2. Elsa can paint a room in 5 hour. If her sister Ruth helps her, they can paint the same room together in 3 hour. How long will it take for Ruth to paint the room alone?

3. The intensity of light produced by a loght source varies inversely as the square of the distance from the source (i= k/d^2). If the intensity of lifht produced 3 ft from a light source is 750 ft-candles, what is the model of the intensity of light as a function of distance from the source?

There's more to it, but i wanna answer them by myself so if you could me please teach or explain me this first and i will do the rest on my book;-;