The expression we have is:

Step 1. Use the binomial square formula:

Applying this formula to the first binomial squared:

Step 2. Apply the formula for the square of a binomial to the second binomial:

In this case, we have some operations to solve before we move on to isolating x. So we solve the operations:

Step 3. Move the terms that are not x squared to the right side of the expression. Remember that when we move one term from one side of the equation to the other, the term must change its sign. We get the following:

Step 4. Combine like terms and arrange terms in order from the greatest exponent to the lowest and leave the independent term at the end:

And that is the final result, which is option A.
Answer: Option A.
Answer:
7000
Step-by-step explanation:
10^3=1000
1000*7=7000
Answer:
378
Step-by-step explanation:
It will also be a multiple of 21 .
As it is divisible by 3 the first possibility is 366 so:-
364 + n = 21m
where n = 2,5,8,11,14...
Trying each number in turn we get:-
364 + 14 = 21m
21m = 378
m = 18
so the answer is 378