请教三道数学题（英文的）(1) six less than a number is the same as five m

请教三道数学题（英文的）
(1) six less than a number is the same as five more than three times the number
(2) four more than twice a number is seventeen
(3) 15 less than the product of a number and 4 is equal to 3 times the sum of 8 and the number
希望可以把题意和解题方法讲明白一点