There are twenty one adults in line at a movie theater. that is three times the number of children in line. how many children were in line.

it's equivalent, so we can say that its equal.

let's call the denominator x and the numerador is 18 less then denominator, x - 18.

multiply

2.x = 5.(x - 18)

2x = 5x - 90

90 = 5x - 2x

90 = 3x

x = 90/3

x = 30

so:

-7/8

step-by-step explanation:

instead of subtracting you add the -6/8 and -1/8