How do you solve x3 equals 4x? - Answers

Restate the question. Solve: x3 = 4x (Algebra can be hard to write with a keyboard.) x3 = 4x x3/x = 4x/x {divide both sides by x} x2 = 4* x = plus or minus radical 2 x = +/- 2 *or you could go: x2 - 4 = 0 (x - 2)(x+2) = 0 x - 2 = 0 or x + 2 = 0 x = 2 or x = -2 x = +/-2 ====== Answer 1: 3x = 4x If you divide both sides by x, you get 3 = 4 So this approach doesn't seem to work. However, if you take all terms to the left side, you get: 3x - 4x = 0 -x = 0 Multiplying by (-1): x = 0 So zero is the solution. The reason the first approach didn't work is because I was dividing by zero. If you do try this - and it makes sense, for more complicated equations - you have to separately analyze the possibility that x = 0.