-2.1b +5.3= b -- 3.1b + 5.3

does is have one solution or infinitely many solutions ? Why ?

infinitely many solutions.

Step-by-step explanation:

Ok, our equation is:

-2.1*b + 5.3 = b - 3.1*b + 5.3

now, simplifyng the right side, we have:

b - 3.1*b + 5.3 = (1 - 3.1)*b + 5.3 = -2.1*b + 5.3

Then our initial expression is:

-2.1*b + 5.3 = -2.1*b + 5.3

So in both sides of the equality we have the exact same thing, so this is a trivial equality.

This means that the equality will remain true for any value of b, which means that we have infinitely many solutions.

if you use photomath right away it will give you the answer not like this app that you have to wait for people.

the answer is y < -3 or   y > 3

-3y > 7 + 2

-3 y > 9

y < -3