``` Integrate[ Boole[{ -2 <= 2 x + 7 y <= 2 && -2 <= 3 x + 6 y <= 2}](6 x^2 + 33 x*y + 42 y^2)^4, {x, -∞, ∞}, {y, -∞, ∞}] ``` > `4096/225` ``` Integrate[(6 x^2 + 33 x*y + 42 y^2)^4, {x, y} ∈ ImplicitRegion[{ -2 <= 2 x + 7 y <= 2 && -2 <= 3 x + 6 y <= 2}, {x, y}]] ``` > `4096/225` ``` (* change of variables *) sol = Solve[{u == 2 x + 7 y, v == 3 x + 6 y}, {x, y}][[1]]; (* {x -> 1/9 (-6 u + 7 v), y -> 1/9 (3 u - 2 v)} *) expr = (6 x^2 + 33 x*y + 42 y^2)^4 /. sol // Simplify; (* u^4 v^4 *) jacobian = Grad[{x, y} /. sol, {u, v}] // Det // Abs (* 1/9 *) Integrate[expr*jacobian, {u, -2, 2}, {v, -2, 2}] ``` > `4096/225`