Given functions rx x3 sx 4x2 and tx 4x 8 determine value

Given functions, r(x) = x/3, s(x) = 4x^2, and t(x) = 4x+ 8, determine value of the function for: a) r(x) = -2 x = __ b) s(x) = 64 x = __ c)t(x)=28 x= __ d) s(x) = 12 x = ___ e)r(x) = 2/5 x ___ f) t(x) = -4 x = ____

Solution

(a)

r(x) = -2

-2 = x/3

x . = -6

(b) s(x) = 64

4x^2 = 64

x = 4

(c) t(x) = 28

4x +8 = 28

x = 5

(d) s(x) =12

4x^2 = 12

x = sqrt3

(e) r(x) =2/5

x/5 = 2/5

x = 2

(f) t(x) =-4

4x +8 = -4

4x = -12

x = -3