Question

8. Which of the following ordered pairs is a solution to f(x) = 1/2x -8?(4, - 4)(2, - 7)(10, 3)(-6, 11)

Answer 1

ANSWER

(2, -7)

EXPLANATION

We want to find which of the ordered pairs is a solution for:

$f(x)\text{ = }\frac{1}{2}x\text{ - 8}$

Ordered pairs are usually given in the form (x, f(x)). That is the value of x and the value of the function of x.

We have to put each of the first values in the ordered pairs in the given function and see if it results in the second value.

=> (4, -4)

$\begin{gathered} f(4)\text{ = }\frac{1}{2}(4)\text{ - 8} \\ f(4)\text{ = 2 }-8 \\ f(4)\text{ = -}6 \end{gathered}$

Not a solution

=> (2, -7)

$\begin{gathered} f(2)\text{ = }\frac{1}{2}(2)\text{ - 8} \\ f(2)\text{ = }1\text{ - 8} \\ f(2)\text{ = -}7 \end{gathered}$

This is a solution.

=> (10, 3)

$\begin{gathered} f(10)\text{ = }\frac{1}{2}(10)\text{ - 8} \\ f(10)\text{ = }5\text{ - 8} \\ f(10)\text{ = }-3 \end{gathered}$

Not a solution.

=> (-6, 11)

$\begin{gathered} f(-6)\text{ = }\frac{1}{2}(-6)\text{ - 8} \\ f(-6)\text{ = -3 - 8} \\ f(-6)\text{ = -11} \end{gathered}$

Not a solution.

The only solution there is (2, -7)