20% of 89.75 is 17.95

so :

the Trina's coupon will subtract the answer by 10%:
10%of 71.8 is 7.18

so the final answer is:

she has to pay $64.62
hope this helps
Answer:
Step-by-step explanation:
Area = length * width
length: x + 3
width: x - 5
A = (x + 3)(x - 5)
Simplify (x + 3)(x - 5) using the FOIL method:
1. First numbers: multiply the first number of each binomial together--x*x = x%5E2
2. Outer numbers: multiply the outer number of each binomial (out of the entire expression, the number farthest to the left (x) and the number farthest to the right (-5))--x*-5 = -5x
3. Inner numbers: multiply the inner number of each binomial--3*x = 3x
4. Last numbers: multiply the last number of each binomial--3*-5 = -15
==> Now, add all of the results together and combine like terms: x%5E2+-+5x+%2B+3x+-+15 = x%5E2+-+2x+-+15
Therefore, A = x%5E2+-+2x+-+15
Answer:
f(x) = 3x⁴ -
- 17x + 
Step-by-step explanation:
To find f'(x), we will follow the steps below:
We will start by integrating both-side of the equation
∫f'(x) = ∫(12x^3 - 2x^2 - 17)dx
f(x) = 3x⁴ -
- 17x + C
Then we go ahead and find C
f(1) = 8
so we will replace x by 1 in the above equation and solve for c
f(1) = 3(1)⁴ -
- 17(1) + C
8 = 3 -
- 17 + C
C =8 - 3 + 17 + 
C = 22 + 
C =
C = 
f(x) = 3x⁴ -
- 17x + 
6 because the small triangle is a dilation of 3