Question

The function \(f\) satisfies
\(f(x) + f(2x + y) + 5xy = f(3x - y) + 2x^2 + 1\)
for all real numbers \(x\), \(y\). Determine the value of \(f(10)\).

Answer 1

can't seem to hit on the right combination

Answer 2

x=10,y=5

Answer 3

in general x=2y

or y=x/2

then you can actually find f(x)

Answer 4

How did you find x = 2y?

Answer 5

2x+y=3x-y

then
2y=x