Don't eliminate, do this instead!

A system of linear equations, not solved by eliminating. We use high school algebra to solve it.

[@aditya-u7s9v]

I love solving these problems!
Consider the cubic polynomial ax^3 + bx^2 + cx + d=f(x)
Now consider the biqaudratic polynoimal g(x) = x^4-f(x)
Observe that as g(x) is monic and has roots at 3,-1,2 and -2
Now from Vietas relations
a= 2+-2+-1+3 = 2
b =7
c = -8
d=-12
as usual thanks for the problem sir!

[@prathamkamath5661]

Lovely observation