Answer:
I assume that we want to find the inverse of the function:
f(x) = 2*x + 10
Remember that the inverse of a function f(x), is a function g(x) such that:
f( g(x) ) = g( f(x) ) = x
Because f(x) is a linear function, we can assume that g(x) will also be a linear function:
g(x) = a*x + b
let's find the values of a and b.
We will have that:
f( g(x) ) = 2*g(x) + 10 = 2*(a*x + b) + 10
And that must be equal to x, then we need to solve:
2*(a*x + b) + 10 = x
2*a*x + 2*b + 10 = x
this must be true for all values of x, so we can separate it as:
(2*a*x) + (2*b + 10) = x + 0
2*a*x = x (one equation for the terms with x)
2*b + 10 = 0
Solving these two equations we get:
2*b = -10
b = -10/2 = -5
2*a*x = x
2*a = 1
a = 1/2
Then the inverse function is:
g(x) = (1/2)*x - 5