A+b+c = 131
b = 7 + 2a and c = a - 12
so a + 7+2a + a-12 = 131
then 4a -5 = 131
then 4a = 136
and a = 34....so b= 75 and c = 22....check 34+75+22=131√
Just multiply or divide the ratio to get each number to 30.
The root is the x intercepts or the zeros of the problem
If I were to graph
(x-5)(x+4)=0
We need a number for x which makes this equation 0
The numbers are 5 or -4
These are the x intercepts of the parabola or roots