Let u(x)=2x1 and w(x)=x2, how do you find u(w(-4)) and w(u(-4))?

1 Answer
Dec 20, 2015

u(w(-4))=31 w(u(-4))=81

Explanation:

w(u(-4))

u(x)=2x1
u(4)=2(4)1 (plug in -4)
u(4)=81 (multiply)
u(4)=9 (add)
w(x)=x2
w(u(4))=(9)2 (plug u(-4)=-9 into w(x))
w(u(4))=81 (square)

u(w(-4))

w(x)=x2
w(4)=(4)2 (plug in -4)
w(4)=16 (square)
u(x)=2x1
u(w(4))=2(16)1 (plug w(-4)=16 into u(x))
u(w(4))=321 (multiply)
u(w(4))=31 (add)

hope this helps