Answer:
Step-by-step explanation:
The first step is getting 4 on the other side so you minus 4 to get 4/5b=9/10b
you then subtract 9/10 from 4/5 in order to do this you need to get 4/5 a denominator of 10, so you take 4/5 times 2/2 to get 8/10
So now you can take 8/10-9/10=-1/10
You now have -1/10b=-4
you then times -10 on both sides to get b by itself
b= -4* -10
b=40
