Let: f(x) = -3x^2 + 5x, g(x) = 4/4x-3, and h(x) = sqrt(25-2x).

Question

Evaluate the following. If a solution does not exist, explain why it doesn't:

(i) f (5/3)
(ii) g(1)
(iii) h(5x-1/2x^2) HINT: Check whether the resultant expression under the square root sign can be written as a perfect square.
(iv) h(8)xg(3/4)

Answer 1

f(x) = -3x² + 5x

Take out factor x

f(x) = x(-3x + 5)

Evaluate f (5 / 3)

Substitute x = 5 / 3 in the function

f(5 / 3) =5 / 3[-3(5 / 3) + 5]

f(5 / 3) = 5 / 3[-5 + 5]

f(5 / 3) = 5 / 3 (0)

There fore f(5 / 3) = 0.

Answer 2

The functions are , and

(ii) 

(iii)

Now substitute this expression ( ) in to function h in place of the x  value.

(iv)