Answer:
you have to start with replacing y with x+7 then -7 from the right side and combine you integers(the letters x) once you are left with just the #x dived until you have 1x and that is how you do these type of questions
Step-by-step explanation:
3x – 2x+7 = 21
1x+7=21
1x=14
–2x – 3x+7 = 21
-6x+7=21
-6x=14
1x=-2.3
–2x + 3x+7 = 7
1x+7=7
1x=0
–2x + 3x+7 = 21
1x+7=21
1x=14
