20.50 * 0.8 = $16.40
16.40 * 0.4 = $6.56
Final selling price = $6.56
8 - 11 = -3. The square root of 25/121 = (the square root of 25) / (the square root of 121) = 5/11 . -3 x 5/11 = -3/1 x 5/11 = (-3 x 5) / (1 x 11) = (-15)/11 = -15/11.
If n = the term number, then:
A(4) = 6-4(4-1)
A(4) = 6-4(3)
A(4) = 6-12
A(4) = -6
A = -1.5
Answer:
first one is not. parallel second one is not and the third one is