I have a question about basic algebra. Ofcourse, you can add something to both sides to make the equation hold true, but where can you not?
Here for example: $10x(3)=10$ and adding 10 to both sides $10x(3+10)=20$ is not going to hold true. Is there like a list I could look at for those kinds of rules?
I'm watching a video of a teacher explaining how to solve a quadratic equation and he just casually adds something to a multiplication and the same on the other side. So I don't really understood how it's possible since on the one side we are not multiplying and on the other we do, that can't really hold the same value?