## breanna1999 one year ago Let f(x)=x^2+x+2 and g(x)=2x^2+5 find f(g(x))

1. anonymous

hint: $$\bf f(x)=x^2+x+2 \qquad {\color{brown}{ g(x)}} =2x^2+5 \\ \quad \\ f(\quad {\color{brown}{ g(x)}}\quad )=({\color{brown}{ g(x)}})^2+({\color{brown}{ g(x)}})+2 \\ \quad \\ f(\quad {\color{brown}{ g(x)}}\quad )=({\color{brown}{ 2x^2+5}})^2+({\color{brown}{ 2x^2+5}})+2$$

2. anonymous

expand and simplify :)

3. breanna1999

I don't get it

4. anonymous

which part?

5. anonymous

notice, the "g(x)" becomes the ARGUMENT for f(x), thus any "x" inside f(x) becomes "g(x)" and it turns out that g(x) is an expression, so once expanded, it looks like so :)

6. anonymous

if we say were to use "cheese" instead than $$\bf f(cheese)=cheese^2+cheese+2$$

7. anonymous

f( value for the variable ) <--- so whatever is in there, the variable, or "x", takes on that

8. anonymous

it just so happens, in this case is a function, g(x)

9. Nnesha

say cheese!!