2 y*(7*y + 4*x) - (2*x + y)
y*(7*y + 4*x) - (2*x + y)^2 при y = -3
y*(7*y + 4*x) - (2*x + y)^2
(-3)*(7*(-3) + 4*x) - (2*x + (-3))^2
-3*(7*(-3) + 4*x) - (2*x - 3)^2
63 - (-3 + 2*x)^2 - 12*x
-(y + 2.0*x)^2 + y*(4.0*x + 7.0*y)
2 2 - 4*x + 6*y
/ 2 2\ -2*\- 3*y + 2*x /