Bethany needs to solve the equation –x2 + 4x = x – 4. What system of equations could she write to help her solve for x ?
Name the solution(s) for her system.

(x) - (y) = (1 + 4i)

this is a direct variation proportion. y = kx

y is the total amount due, k is the constant of variation, and x is the number of texts sent.

plug in the 3.20 and the 16 to solve for the "k". this is the constant of proportionality. it is the value that will not change.

3.20 = k(16). solving you get $.20 per text.

the equation would then be y = .20x

middle maybe?

step-by-step explanation: