If I only knew how...

If I only knew how...

I've already posted a worksheet above. For my second question I have two functions: y=x and y=3x^2. They are implicit defined and I can't convert them. I had given the first one the letter A en the second the letter B. When I tried to solve(A=B) it gave an error. I suspect it's because they are implicit defined. What could I do to solve this intersection?

I've already posted a worksheet above. For my second question I have two functions: y=x and y=3x^2. They are implicit defined and I can't convert them. I had given the first one the letter A en the second the letter B. When I tried to solve(A=B) it gave an error. I suspect it's because they are implicit defined. What could I do to solve this intersection?