Answer:
See explanation
Step-by-step explanation:
Assuming the given equation is

To solve for r, we first divide both sides by a.

We now subtract 5 from both sides:

We now divide through by - 1 to get:

Or

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For numbers 9 and 10, we are dealing with negative exponents.
The rule of exponents states that any quantity b, taken to the power -n, equals the reciprocal of b, taken to the nth power.
Example: x⁻³ = 1 / x³
Number 9: ( 3 / y² ) ⁻³
Step 1: take the reciprocal:
( 3 / y² ) ⁻³ = ( y² / 3 ) ³
Step 2: distribute the exponent
( y² / 3 ) ³ = y⁶ / 27
Try to do number 10 on your own. If you have any questions, comment.