Question

Find each unknown function value or x value for f(x) = 4x - 7 and g(x) = -3x + 5

Answer 1

Step 1

Find f(2)

$To\text{ do this we substitute for f= 2 in f(x)}$$\begin{gathered} f(x)\text{ = }4x-7 \\ f(2)\text{ = 4(2) -7 = 8 - 7 = 1} \end{gathered}$

Step 2

Find f(0)

$f(0)\text{ = 4(0) -7 = 0 - 7 = -7}$

Step 3

Find f(-3)

$f(-3)\text{ = 4(-3) -7 = -12 -7 = -19}$

Step 4

Find x, when f(x) = -3

$\begin{gathered} f(x)\text{ = -3}--------------(1) \\ f(x)\text{ =4x-7}---------------(2) \\ \text{Equate both equations} \\ -3=4x-7 \\ -3+7\text{ = 4x} \\ 4x\text{ = 4} \\ x\text{ = }\frac{4}{4}=1 \end{gathered}$