The answer is B, you should really learn how to calculate these yourself though because they come up a lot.
Once the numbers have the same base and exponents, we can add or subtract their coefficients.Here are the steps to adding or subtracting numbers in scientific notation:Determine the number by which to increase the smaller exponent by so it is to the equal larger exponent
Let m and j be the current ages of Matthew and Jenny, respectively.
Now, Matthew is 3 times as old as Jenny, so the variables are in the following relation:

In 7 years, both of them will be 7 years older, i.e. their ages will be m+7 and j+7, and Matthew will be twice as old:

Now, remembering that m=3j, we can rewrite the second equation as

So, Jenny is 7 and Matthew is 21 (he's 3 times older).
In fact, in 7 years, they will be 14 and 28, and Matthew will be twice as old.
Answer:
Angles that are directly across from each other
Step-by-step explanation:
Vertical angles are angles that are directly across from each other, forming an x. They always have the same degree