N = nickels and q = quarters
0.05n + 0.25q = 1.90
n = 2q + 3
0.05(2q + 3) + 0.25q = 1.90
0.10q + 0.15 + 0.25q = 1.90
0.10q + 0.25q = 1.90 - 0.15
0.35q = 1.75
q = 1.75/0.35
q = 5 ......there are 5 quarters
n = 2q + 3
n = 2(5) + 3
n = 10 + 3
n = 13 <=== there are 13 nickels
30 = 60% of x
x being our variable, we need to figure out what x equals. Use the formula I put in the attachment. Multiply 30 by 60, and then divide the product by 100. That will give you the answer :)
The answer is A. 2, -2
Hope I helped!
Let me know if you need anything else!
~ Zoe
Answer:
R.H.S:
= cos ( 90 - theta )
= cos (90) cos(theta) + sin(90) sin(theta)
= 0 + sin(theta) =>[ cos(90) = 0 , sin(90) = 1]
= sin(theta)