Since you are writing in Romanian, i'll translate first the question.
The sum of three numbers is 2450. The first number is 250 higher than the second and third higher than 180. What are the numbers?
So making the equation.
X + Y + Z = 2450
X = first number
Y = second number
Z = third number
Equation 1.
X = 250 + Y
Equation 2.
X = 180 + Z
Equation 3.
250+Y = 180+Z
Y= Z-70
Equation 4
(Z+180)+(Z-70)+Z = 2450
3Z = 2450 - 110
3Y = 2340
Y = 780
X = 1030
Z = 640
