It is good equation. Look, that:
81 = 3 x 3 x 3 x 3 = 3^4.
So you have to solve:
3^x = 3^4
exponents have to be the same, so
x=4
That's mean that A(4) = 81
You can make an equation to solve this, but establishing knowns, unknowns, and relationships.
# in spring wash = x
# in summer = x + 14
Total Washes = 96
we know:
total = summer + spring
96 = (x) + (x + 14)
96 = 2x + 14
82 = 2x
"x" = 41
So for this problem, we will be using the exponential equation format, which is y = ab^x. The a variable is the initial value, and the b variable is the growth/decay.
Since our touchscreen starts off at a value of 1200, that will be our a variable.
Since the touchscreen is decaying in value by 25%, subtract 0.25 (25% in decimal form) from 1 to get 0.75. 0.75 is going to be your b variable.
In this case, time is our independent variable. Since we want to know the value 3 years from now, 3 is the x variable.
Using our info above, we can solve for y, which is the cost after x years.

In context, after 3 years the touchscreen will only be worth $506.
You're asking for the square root of 32. you can actually do this on a calculator really easily. just type in the number (in this case, 32) and press the square root symbol (looks like a calculator). the square root of 32 is a long string of decimals, but it's approximately 5.7 :) good luck