Functions Practice AK

$f(x)=3x+7$

Find the value of:

1. $f(2)= \mathbf{3(2)+7=13}$
2. $f(3)= \mathbf{3(3)+7=16}$
3. $f(5)= \mathbf{3(5)+7=22}$
4. $f(10)= \mathbf{3(10)+7=37}$

$f(2)=7$

5. Which of the following could be f(x)?
   1. $f(x)=x+2 = 2+2=4$ no
   2. $f(x)=x^2-1= 4-1=3$ no
   3. $f(x)=3x-1= 6-1=5$ no
   4. $f(x)=x^2-2= 4-2=2$ no
   5. ${f(x)=x^3-1= \mathbf{8-1=7}}$ yes

$f(x)=2x-4$

$g(x)=\dfrac{x}{2}+3$

Find the value of:

6. $f(4)=2(4)-4=4$
7. $g(3)=\dfrac{3}{2}+3=4.5$
8. $f(g(2))=f(\dfrac{2}{2}+3)=f(4)=2(4)-4=4$
9. $g(f(1))=g(2(1)-4)=g(-2)=\dfrac{-2}{2}+3=-1+3=2$
10. $f(g(f(2)))=f(g(2(2)-4)=f(g(0))=f(\dfrac{0}{2}+3)=f(3)=2(3)-4=2$