6 times a number is 6x because we dont know the number so we assign x to the unknown then multiply by 6. Decreased by 10 simply means subtract 10. "is eight" tells you what the previous is equal to. Now, you add 10 to the - 10 to isolate x on one side of the equation. you are left with 6x = 18 because we added 10 to 8. then you want to get x alone so you divide 6x by 6, and 18 by 6. you get x=3, your answer.