One way to solve this problem is to substitute the values of x from the table and see which function
results in the corresponding y-values. The correct answer, (D), will give an outcome of each y-value
when the x-value to its left is plugged in for x. For example, 3(1) − 4 = 3 − 4 = −1, so the first pair
satisfies the equation. Since 3(3) − 4 = 9 − 4 = 5, the second pair also satisfies the equation, and so on.
An alternative method would be to input the x- and y-values into two separate lists on a graphing
calculator and perform a linear regression on the data. This approach may prove to be much less
time consuming than trial and error; however, you need to be both familiar with and comfortable
with the method for finding a linear regression on your particular calculator.
Here is a question in which the calculator is essential.
It is best, however, to use the calculator on the last step and enter both log functions in the same set
of keystrokes. If you calculate the log of 18.52 alone, you will get 1.267640982. You could make
careless errors and waste precious time as you try to retype this number into the calculator. Another
approach to this problem could be to try each answer choice, using the power key on your keypad.
In the following problem, a graphing calculator would give you a decided advantage:
Solve for x:7 x = 18.52