Answer:
y = x + 7
Step-by-step explanation:
Your equation is -3x + 3y = 21
You want to get the y by itself (this would be easiest if you kept the y on the left side of the equation since this is where the y formally is). To do this, you need to get the -3x on the other side. Since the integer is negative, you are going to add the integer on both sides (this will cancel out the -3x on the left side since you are doing the opposite of the integer). This is shown below.
-3x + 3y = 21
+3x +3x
3y = 3x + 21
The part on the question on the right side is 3x + 21. The 3x is shown first because the x of these equations are always first. The 21 is + 21 because the 21 is already positive.
Now, we need to get the 3y to be y by itself. To do this, we need to divide the equation it total by 3. Since the 3 is attached to the y, this represents multiplication. You always want to do the opposite to do these equations. This step is shown below.
3y = 3x + 21
/3
3y divided by 3 = y
3x divided by 3 = x
21 divided by 3 = 7
Now plug these into the equation.
y = x + 7
I hope this helps! Have a good day, and please mark brainliest ^-^
