The serial number on a bill consists of a letter followed by eight digits and then a letter. How many serial numbers are possible, giving the following conditions (a) letters and digits cannot be repeated (b) letters and digits can be repeated (c) the letters are nonrepeated consonants and the digits can be repeated ( let y be a consonant)

(c, 0) i might be wrong so don't put full faith on my answer

step-by-step explanation:

the ratio of red paint to blue paint is always 9/7. that means that, whatever x's value, (4x+12)/(4x-4) has that same ratio. so, set up an equation and cross-multiply to solve for x:

9/7 = (4x+12)/(4x-4)

9(4x-4) = 7(4x+12)

36x - 36 = 28x + 84

8x - 36 = 84

8x = 120

x = 15

the answer is d

for problems like this theres an app, its photomath that explains the problem and gives the answer hope i

since no one answered yet i will give it a shot, not completely sure tho.

i think it should be y=cos(x+2pi), (third answer, answer c)

good luck.