Answer: your welcome
Explanation:
Let x = the certain number
"A certain number was tripled 3x
"then decreased by 10": 3x - 10
"then doubled": 2*(3x-10)
"Then increased by 2": 2(3x-10)+2
"result was 5 times original number":
2(3x-10)+2 = 5x
6x - 20 + 2 = 5x
6x - 5x = 20 - 2
x = 18
Check (very important):
Is 2*(3*18 - 10) + 2:= 5*18 ?
2*(54-10) + 2 = 90 ?
2*(44) + 2 = 90 ?
90 = 90 ?yes