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Current time:0:00Total duration:2:13

Video transcript

If x-- and the operator here is this x with a circle around it, so maybe we'll call it circle-x. If x circle-x y is equal to x plus 3y, and x-- I'll call that circle-plus. So it's not plus, it's a different operator. It's a new operation, and we're defining it here. And x circle-plus y is equal to 4x squared minus y squared, find negative 2 circle-plus the quantity three circle-cross, or circle-x minus 1. So if we just break it down, we use these definitions, it should hopefully be pretty straightforward. So let's evaluate 3 circle-x negative 1. So 3 circle-x negative 1. Well, they define that as whatever is x plus 3 times whatever is y. So this is going to be whatever is x, so that is our 3, plus 3 times whatever is y. Well, that's going to be negative 1. So this is 3 plus negative 3, which is equal to 0. So this whole part right over here is equal to 0. So our entire expression simplifies down to negative 2 circle-plus 0. And now we can use this definition right here. x circle-plus y is equal to 4x squared minus y squared. So in this situation, our x-- let me circle it over here. Our x is negative 2 , and our y is 0. So this is going to be equal to-- it's going to be equal to 4 times x squared. So that's negative 2 squared. 4 times negative 2 squared minus y squared. Well, y is just 0. Minus 0 squared. And 0 squared is obviously just 0. And so this simplifies to 4 times negative 2 squared. Negative 2 squared is positive 4. So it's 4 times 4. So it simplifies to 4 times 4, which is equal to 16. And we're done.