May 27th 2019 archive

Week 15- pre calc 11

This week in PreCalc 11 we revisited the idea of rational expressions and learned how to add together rational expressions with variables in the denominator.

for example:

when we add the rational expressions together the denominator needs to be the same so we take a common factor of the two denominators.

And we always need to remember that the denominator connot equal 0. So if the denominator is 8x x cannot equal 0. And if it is 8 + x, x cannot equal -8.

example:

6/5x + 4/3x

we would find the common factor of both denominators which in this case is 15 so we would multiply the top and bottom so the bottom equals 15

6/5x + 4/3x -> 18/15x + 20/15x

and then we could add them together

18+20/15x

38/15x is your answer

 

and if you could from this step you could simplify this expressions. (notice there isn’t an equal sign because expressions don’t contain equal signs)

last we need to write the restrictions for x so in this case x cannot equal 0.