Step-by-step explanation:
51 is not a prime number because it is divisible by 1,3 and 17
and we know prime number are only those number who arenot divisible by any other number except 1
Answer:
720
Step-by-step explanation:
multiply 12x10=120 then 120x6=720
Answer:
72.5m/hr
Step-by-step explanation:
Divide 870 by 12 to represent how many miles David drove in 1 hour.

David drove 72.5 miles per hour.
Answer:
(7w + 9x)(7w - 9x)
Step-by-step explanation:
Given expression;
49w² - 81x²
Now to solve the problem;
49w² - 81x² = 7²w² - 9²x²
Using differences of two squares;
x² - y² = (x + y)(x - y)
So;
7²w² - 9²x² = (7w + 9x)(7w - 9x)