The product of a three times a number and 7 is 63. find the number

Set it up algebraically

3 times a number so 3x where x = the mystery number

times 7 so 3x*7

and it equals 63 so,

3x*7=63

this can be further simplified to

21x=63

then just divide both side by 21 to get your answer

(21/21) x = (63/21)

so x=3