The answer is A. You have to isolate the variable(f) by subtracting 0.2 from both side. When youve done that, the answer should be -3.2
Answer:

Step-by-step explanation:
start by foiling out the given function

next, use the power rule to find the derivative
power rule: To use the power rule, multiply the variable's exponent n, by its coefficient a, then subtract 1 from the exponent. If there's no coefficient (the coefficient is 1), then the exponent will become the new coefficient.

Answer:
a = 13
Step-by-step explanation:
Hello!! This is how you do it!!
a - 7 = 3 (2)
a - 7 = 6
+ 7. +7
a = 13
Y = 1/4x - 1....the slope here is 1/4....but for a perpendicular line we need a negative reciprocal slope...all that means is " flip " the slope and change the sign. 1/4....flip it....4/1.....change the sign....-4/1 or just -4. So our perpendicular line will have a slope of -4. The only one in ur answer choices with a slope of -4 is D.....so ur answer has to be D.