Which of the following cannot be the graph of a function of X?

Why not? Because it fails the vertical line test. Here it is possible to draw a single straight vertical line through more than one point on the curve. That's why choice D is not a function. Choices A,B,C are functions because it's impossible to draw a single vertical line through more than two points on the curve, and therefore we can say they pass the vertical line test.

Side note: choices B and C fail the horizontal line test, so these functions are not one-to-one.

the answer is:

the correct option:

b.

to solve the problem, we need to remember how to operate to simplify exponential expressions using the logarithms.

we are given the equation:

then, using placing logarith with base 7 on both sides of the equation, we have:

so, rounding the obtained result to two decimal places (nearest hundreth), we have:

hence, we have that the correct option:

b.

have a nice day!

part a: 1.08

part b: 27.59