Problema Solution
the sum of three numbers is 12. one of the numbers is twice the sum of the other two numbers. this same number is also equal to one of the other numbers decreased by triple the third number. what are the three numbers.
Answer provided by our tutors
let 'x' represent one number and let 'y' represent one of the other numbers
twice the sum of the other two numbers is 2(x+y)
(2(x+y)-x) is equal to one of the numbers less than triple of the others, so we let x-3x substitute for y
x+y+2(x+y)=12
2(x+y)-x=x-3x
click here to solve the system
x=-8
y=12
2(-8+12)=2(4)=8
So the numbers are -8, 8 and 12.