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

1. jdoe0001

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. jdoe0001

expand and simplify :)

3. breanna1999

I don't get it

4. jdoe0001

which part?

5. jdoe0001

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. jdoe0001

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

7. jdoe0001

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

8. jdoe0001

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

9. Nnesha

say cheese!!