Greatest common factor of 7

Greatest common factor (GCF) of 7 and 15 is 1. We will now calculate the prime factors of 7 and 15, than find the greatest common factor (greatest common divisor (gcd)) of the numbers by matching the biggest common factor of 7 and 15.

i think ur answer is   (3,-1)

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: