functions Don't understand a bit!

[waici]

My son is in 11th grade and had to be absent because of a mouth surgery now in class they're discussing a new material and he's lost and he is having trouble in the class. I've tried to help but don't understand this modern math. I've searched everywhere for help so if someone can explain us how to solve this we''ll appreciate so much. He has the answers as he copied them from a friend's notebook but we don't understand that procedure to get to that answer.

FIRST THEY GIVE THE FOLLOWING: A] f(x) + g(x) B] f(x) - g(x) C] f(x) X g(x) D] f(x) / g(x)

THEN THE FOLLOWING EXERCISES: 1] f(x)=x-1 2] f(x)=2 3] f(x)=x^2
g(x)=9-x g(x)=3 y(x)=4

WE UNDERSTAND THAT FOR EACH NUMBERED EXERCISE A DIFFERENT PROCEDURE HAS TO BE DONE APPLYING SUM-SUBSTRACTION-MULT-DIVISION

PLEASE HELP!!!!!!!!!!!!!!!!!!!!!!!!!!!!! :shock:

 

[masters]

My son is in 11th grade and had to be absent because of a mouth surgery now in class they're discussing a new material and he's lost and he is having trouble in the class. I've tried to help but don't understand this modern math. I've searched everywhere for help so if someone can explain us how to solve this we''ll appreciate so much. He has the answers as he copied them from a friend's notebook but we don't understand that procedure to get to that answer.

FIRST THEY GIVE THE FOLLOWING: A] f(x) + g(x) B] f(x) - g(x) C] f(x) X g(x) D] f(x) / g(x)

THEN THE FOLLOWING EXERCISES:
1] f(x) = x - 1
g(x) = 9 - x

Hi waici,

Have no fear. You've come to the right place. This is just an exercise in adding, subtracting, multiplying and dividing functions. Very straight forward.

[1] \(\displaystyle f(x)=x-1\) and \(\displaystyle g(x)=9-x\)

[A]. \(\displaystyle f(x)+g(x)=(x-1)+(9-x)=x-1+9-x=\boxed{8}\)

. \(\displaystyle f(x)-g(x)=(x-1)-(9-x)=x-1-9+x=\boxed{2x-10}\)

[C]. \(\displaystyle f(x) \cdot g(x)=(x-1)(9-x)=9x-9-x^2+x=\boxed{-x^2+10x-9}\)

[D] \(\displaystyle \frac{f(x)}{g(x)}=\frac{x-1}{9-x}=\boxed{-\frac{x-1}{x-9}}\)

Use this worked example as a model for the others. Good luck.