Evaluate each of the following f7 when fx x2 4 x8x 7 g 5

Evaluate each of the following. f(7) when f(x) = x^2 - 4 + x/8x - 7 g(- 5.5) when g(x) = - 4x^2 + 1.8x - 2(9 - x)/7.1 - 2x g(m) when g(x) = 2/3 x - 5x^3 + x(x + 4) f(x + 2) when f(x) = 5x^2 + 6x - 11

Solution

a) f(x) = (x^2 + x +4)/(8x -7)

f(7) plug x= 7 in f(x)

f(7) = (7^2 + 7 +4)/(7*8 -7) = 60/49

b) g(x) = (-4x^2 +1.8x -2(9 -x) )/(7.1 - 2x)

g(5.5) = ( -4*5.5^2 +1.8*5.5 - 2(9-5.5) )/( 7.1 -2*5.5)

= 30.28

c) g(x) = 2x/3 - 5x^3 +x(x+4)

g(m) = 2m/3 - 5m^3 +m(m+4)

   = -5m^3 + m^2 +14m/3

d) f(x) = 5x^2 +6x -11

plug x=x+2

f(x+2) = 5(x+2)^2 +6(x+2) -11

= 5(x^2 +4 +4x) +6x +12 -11

= 5x^2+26x + 21