Solve x² - 4 = 5 by graphing the related function.
There are two solutions 1 and -1
There is one solution 1
There are no real number solutions.
There are two solutions 3 and -3

Solution:

Solving x² - 4 = 5 we have

x² - 4 = 5

x²  = 9

x = ±3

x = ±3 are the zeroes of the function y = x² - 9 as evident from the graph below:

The zeroes of the graph reveal x = -3 and x = 3

Solve x² - 4 = 5 by graphing the related function

Summary:

Solving x² - 4 = 5 by graphing the related function we get two solutions 3 and -3