Justin weighs 15 pounds less than greg weighs. half of greg’s weight is 75 pounds less than justin’s weight. how much does each of them weigh?

J = g - 15 Justin weighs 15 lbs less then Greg
1/2g = j - 75 --- half of gregs weight is 75 lbs less then justins

so we sub g - 15 in for j in the 2nd equation
1/2g = j - 75
1/2g = g - 15 - 75
1/2g - g = - 90
1/2g - 2/2g = -90
-1/2g = -90
g = -90 * -2
g = 180

j = g - 15
j = 180 - 15
j = 165

so justin (j) weighs 165 lbs and greg (g) weighs 180 lbs