Which expression is equal to f(x) + g(x) given f(x) = x² + 10 and g(x) = x – 3 ?

a. 2x² + 7
b. 7x² + x - 3
c. x² + x + 7
d. x² - x - 10

Question

Which expression is equal to f(x) + g(x)  given f(x) = x² + 10 and g(x) = x – 3 ?

a.  2x² + 7	 
b.  7x² + x - 3	
c.  x² + x + 7	
d.   x² -  x - 10

calculusxy · Answer

You would just to combine the two functions of $f(x)$ and $g(x)$. 

$f(x) = x^2 + 10$
$g(x) = x - 3$

$\bf \color{red}{f(x)} + \color{green}{g(x)} = \color{red}{x^2 + 10} + \color{green}{x-3}$

Now you just need to combine the like terms to simplify the expression.

help_me_pls · Answer

I think that it's A but I also think it may be C

mathmale · Answer

Please share your thoughts.  What makes you think (tentatively) that "it's A" and "it may be C?"  

Show your work, please.  Then I could give you meaningful feedback.

calculusxy · Answer

It cannot be A because there's no two $x^2$ terms that you can combine to make $2x^2$. 

Here's how I used to combine like terms especially when there were different types of variables raised to different powers. |dw:1476632687002:dw|