I think you substitute 189 for the letter t.
You actually do substitute.
Both A and C is true. However, even though a rectangle can be a parallelogram, a parallelogram is a quadrilateral, so the answer is A.
I hope this helps!
Answer: B and D
Step-by-step explanation:
First, solve the terms inside of the parenthesis. As a general rule, whenever you multiply two terms that have the same base, you can add their exponents.
Applying this rule, the base in the problem is 6, and the exponents are 3 and -4. The sum of 3 and -4 leaves -1. Therefore, this is one of our solutions:

When you have an exponential term raised to another exponent, you can simply multiply the exponents. In the previous solution given above, multiply -1 and -3 to get 3. Therefore our second solution is:

Since distance equals speed times time (d = st), we have
t = d/s
where d = 120 miles and s = 15 miles per hour
t = d / s
t = 120 / 15
t = 8
It will take 8 hours to drive 120 miles at a speed of 15 miles per hour.