Question

still cant get the correct answer. Minimize F=x^2+y^2 with x + 2y = 10.

Answer 1

I think you want to use substitution -

using x+2y =10, so
x = 10-2y

replace an x in the F equation with that, so
\[\large F = (10-2y)^2+y^2\]

Try expanding and simplifying.

Answer 2

still got the wrong answer

Answer 3

Don't just tell us you got the wrong answer... show your work so we can see where you're going wrong.