Step-by-step explanation: First you distribute the 12 to (10-x). That then gives you 15x+120-12x=141. Now you combine like terms. So you do 15x-12x=3x. Your new equation now is 3x+120=141. Subtract 120 from 141 and mark it out. That leaves you with 3x=21. Divide both sides by 3. Your final answer is x=7.
