Drizzle some vegetable oil in a large pot of boiling salted water. Add linguine and cook according to package directions.
While the pasta is cooking, in a large heavy skillet melt the butter and olive oil over medium-low heat. Add the garlic and sauté for 1 minute. Add the shrimp, ½ teaspoon of salt, and the pepper and sauté the shrimp until they have just turned pink, about 5 minutes, stirring often. Remove from heat. Add parsley, lemon zest, lemon juice, lemon slices, and red pepper flakes.
When the pasta is done, drain it and immediately add it to the shrimp and sauce, toss well and serve.