Respuesta :
[tex]20-x=15\\-x=15-20\\-x=-5\\x=5[/tex]
If x = 5 then 3x = 15 because 3(5) = 15 substitute x = 5.
Answer: 15
Step-by-step explanation: 20-x=15
-x=-5
x=5
3x = 3(5)
3x = 15
[tex]20-x=15\\-x=15-20\\-x=-5\\x=5[/tex]
If x = 5 then 3x = 15 because 3(5) = 15 substitute x = 5.
Answer: 15
Step-by-step explanation: 20-x=15
-x=-5
x=5
3x = 3(5)
3x = 15