Question

If f(x) = -2x + 8, and f(k) = -10, what is the value
of k? step by step please

Answer 1

Hello there!

We are given the function:

`\displaystyle \large{f(x) = - 2x + 8}`

We want to find the value of k. First, we know that f(k) is -10. We substitute x = k and f(x) = -10.

`\displaystyle \large{f(k) = - 2k + 8} \\ \displaystyle \large{ - 10 = - 2k + 8}`

Solving the equation. First, we subtract both sides by 8.

`\displaystyle \large{ - 10 - 8 = - 2k +8 - 8} \\ \displaystyle \large{ - 18 = - 2k} \\`

Divide both sides by -2.

`\displaystyle \large{ ( - 18)/( - 2) = ( - 2k)/( - 2) } \\ \displaystyle \large{ 9= k}`

Therefore, k = 9

When we substitute k = 9 in f(k), the value is -10.

Let me know if you have any questions!

Topic: Linear Function

Answer 2

Value of k is 9

Explanation:

-2x + 8 = -10

-2x = -10 - 8

-2x = -18

x = -18/-2

x = 9

f(x) = f(k)

x = k

9 = k