Answer
(a) $f(2,1)=5$, (b) $f(1,2)=3$, (c) $f(0,0)=1$, (d) $f(1,-3)=-2$, (e) $f(3a,a)=9a^3+1$, (f) $f(ab,a-b)=(ab)^2(a-b)+1$
Work Step by Step
(a) Substitute $x=2$ and $y=1:$
$$f(2,1)=2^2\cdot1+1=4+1=5$$
(b)Substitute $x=1$ and $y=2:$
$$f(1,2)=1^2\cdot2+1=2+1=3$$
(c)Substitute $x=0$ and $y=0:$
$$f(0,0)=0^2\cdot0+1=0+1=1$$
(d) Substitute $x=1$ and $y=-3:$
$$f(1,-3)=1^2\cdot(-3)+1=-3+1=-2$$
(e) Substitute $x=3a$ and $y=a:$
$$f(3a,a)=(3a)^2\cdot a+1=9a^3+1$$
(f) Substitute $x=ab$ and $y=a-b:$
$$f(ab,a-b)=(ab)^2\cdot(a-b)+1$$
