LCD
Least Common Denominator — multiply every term to clear all fractions at once
EXCLUDE
Any x making a denominator = 0 is FORBIDDEN — find these first
CHECK
Always plug your answer back in — it might be an excluded value
EXTRANEOUS
Looks like a solution algebraically, but is excluded → throw it away
CROSS-MULTIPLY
a/b = c/d → a·d = b·c (only when each side is ONE fraction)
FACTOR
Factor denominators first — you'll spot the LCD and excluded values fast