Answer:
1. Rewriting the expression 5.a.b.b.5.c.a.b.5.b using exponents we get: 
5. 
6. 
7. 
Step-by-step explanation:
Question 1:
We need to rewrite the expression using exponents
5.a.b.b.5.c.a.b.5.b
We will first combine the like terms
5.5.5.a.a.b.b.b.b.c
Now, if we have 5.5.5 we can write it in exponent as: 
a.a as
b.b.b.b as: 
So, our result will be:

Rewriting the expression 5.a.b.b.5.c.a.b.5.b using exponents we get: 
Question:
Rewrite using positive exponent:
The rule used here will be:
which states that if we need to make exponent positive, we will take it to the denominator.
Applying thee above rule for getting the answers:
5)
6) 
7) 
We know that
so, we get

Answer:
4 5 6 7
Step-by-step explanation:
Equation: 21+n=43.23
Process to find n
21+n=43.23
Subtract 21 from both sides
n=22.23
This will generate a line quickly dropping from left to right, with an x-intercept of 0.4 and a y-intercept of 2.
See the attached image for the actual graph.
7(3r-1)-(r+5)=-52
21r-7-r-5=-52
21r-r-5-7=-52
20r-12=-52
Add 12 to both sides
20r=-40
Divide by 20
r=-2