How do we solve for an unknown number in an equation?
X's Great Reveal
How do we solve for an unknown number in an equation?
Somewhere in an equation, a number is hiding. We don't know its name, so we call it x — the mystery guest at the party. Solving an equation is just polite detective work: we coax x out from behind whatever's covering it, until it finally stands alone and tells us who it is.
Here's the one rule that runs the whole show: an equation is a balanced scale. The left side weighs exactly the same as the right side — that's what the equals sign promises. Whatever you do to one pan, you must do to the other, or the scale tips and the promise breaks.
