Question

The graph of the function f(x) = log5 (x) is stretched vertically by a factor of 2, shifted to the left by 8 units, and shifted up
by 3 units.
Find the equation of the function g(x) described above.

Answer 1

Answer:

We start with y = g(x) = f(x)

First, we have a vertical stretch by a factor of 2.

A vertical strech by a factor of A will be g(x) = A*f(x)

then in this case A = 2, so we have g(x) =  2*f(x)

Now we have it shifted left by 8 units.

We know that f(x - A) shift right the graph by A units (A positive), here A = 8.

then we have: g(x) =  2*f(x - 8)

Now we want shift up 3 units, if we have y = f(x) we can shift the graph up by A units as: y = g(x) + A (for A positive)

Then we have: g(x) =  2*f(x - 8) + 3

now, our function was f(x) = Log₅(x)

then g(x) = 2*log₅(x - 8) + 3.