Suppose that y is directly proportional to x, and y = 210 when x = 14. what is the constant of proportionality?
a) 1/15
b) 13
c) 15
d) 17

C

Step-by-step explanation:

In the attached file

5   1/4   miles per hour

step-by-step explanation:

15   3/4 / 3 = 5   1/4

hello from mrbilldoesmath!

answer:

25x^2 + 90x + 84

discussion:

mn(x) = m(n(x)) = m( 5x + 9) =

(5x + 9)^2 + 3 =>

25x^2 + 90x + 9^2 + 3 =

25x^2 + 90x + 84                 (as 9^2 = 9*9 = 81)

which is the second choice

regards,  

mrb

p.s.   i'll be on vacation from friday, dec 22 to jan 2, 2019. have a great new year!