Answer:
Step-by-step explanation:
If
, then 
Now, puting
value in the other equation, we have

Therefore, is a cubic equation
Answer:
-13 or 13
Step-by-step explanation:
Since we are looking for the square root of 169, we realize that 13 multiplied by itself equals 169. Negative 13 does the same, so it is the answer.
Answer:
131.95cm
Step-by-step explanation:
Circumference of a circle is 2 × pi × r
= 2 × pi × 21
= 131.95 cm
U didn’t put a picture of the question
21 is the least common denominator of 7 and 3