I’m going to answer them for you In English
1: 3x = 15
We divide 3 from both sides
X= 5
2: 2a + 5 = 25
Take the 5 to the other side the sign will be negative 25-5= 20
2a = 20
Divide both sides by 2a
You will get a= 10
Question 8: -7b + 5 = 4b + 13 what is b?
You will collect the like term first
-7b -4b = -5 + 13
-11b = 8
Divide both sides by 11 you get -1.37.
Question 12: x/4 = 5 what is x?
You do cross multiplication the number doesn’t have any denominator it’s always 1
1.x = 1x
4.5= 20
1x= 20
X=20
Hope this helped I didn’t do some of them sorry