Answer:
9
Step-by-step explanation:
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.
Answer:
A = 14.2/1.1 hours
B = 5.091 hours
Step-by-step explanation:
Formulate 2 simultaneous equations
5.7A + 6.8B = 111.40..........(1)
A +B =18...............................(2)
Multiply each item in (2) by 5.7 to get
5.7A + 5.7B = 97.2............(3)
subtract (1) - (3) on each side
5.7A -5.7A + 6.8B - 5.7B = 111.40 -97.2
1.1B = 14.2
B = 14.2 /1.1
to get A use equation (2)
A = 18 - B
A = 18 - 14.2/1.1 = 5.091
1 inch equals four 4 because 32 divided by 4 is 8 and 40 divided by 4 is 10