Answer:
n= 4f/5+90
Step-by-step explanation:
f= 5(n−90)
/4 (simplify)
f * 4=5(n−90) (multiply 4 on both sides)
4f=5(n−90) (regroup)
4f/5
=n−90 (divide 5 on both sides)
4f/5
+90=n (add 90 to both sides)
Answer:
136
Step-by-step explanation:
(6-10i)(6+10i)
36 +60i - 60i - 100i²
36 - 100i² (i² = -1)
36 + 100
136
The period of a sinusoid

is

, so any range such that

will give two complete periods.
Answer:
r = 9
Step-by-step explanation:
cross multiply
9 * r = 81
9r = 81
divide both sides by 9
r= 81/9
r = 9