What colors do you mix together to make yellow?

Nothing can be mixed to create yellow, as yellow is a primary color, assuming you're asking about paint. (subtractive)

But if you're working with colours, as the below example specifies, green and red light mix to make yellow light. (additive)

Another view: sorry that's wrong...otherwise on a component feed into your TV there would also be a Yellow lead. To give you a clue there is R, G, B meaning Red, Green and Blue, no yellow surprise surprise, try again.. Red and green make yellow, Yellow is not a primary colour....Red, Green and Blue are the only primary colours.