Equilateral triangle have the same side lengths. Perimeter = sum of all sides
(4x - 3) + (4x - 3) + (4x - 3) = 63
Remove parentheses
4x - 3 + 4x - 3 + 4x - 3 = 63
Combine like terms
12x - 9 = 63
12x = 72, x = 6
Solution: x = 6
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
Hello,
n=1,2,3,.... and not 0
Answer B a(n)=-2*n
X has infinity solutions.