Your answer is D. 16x² - 56xy + 49y².
A perfect square trinomial is the result of a squared binomial, like (a + b)². Using this example, the perfect square trinomial would be a² + 2ab + b², as that is what you get when you expand the brackets.
Therefore, to determine which of these is a perfect square trinomial, we have to see if it can be factorised into the form (a + b)².
I did this by first square rooting the 16x² and 49y² to get 4x and 7y as our two terms in the brackets. We automatically know the answer isn't A or B as you cannot have a negative square number.
Now that we know the brackets are (4x + 7y)², we can expand to find out what the middle term is, so:
(4x + 7y)(4x + 7y)
= 16x² + (7y × 4x) + (7y × 4x) + 49y²
= 16x² + 28xy + 28xy + 49y²
= 16x² + 56xy + 49y².
So we know that the middle number is 56xy. Now we assumed that it was (4x + 7y)², but the same 16x² and 49y² can also be formed by (4x - 7y)², and expanding this bracket turns the +56xy into -56xy, forming option D, 16x² - 56xy + 49y².
I hope this helps!
Answer:
8
Step-by-step explanation:
x - 3 = 5
x = 5 + 3
x = 8
Therefore, the number is 8.
-3+7=4 should be your answer
Answer:
41,055
Step-by-step explanation:
If there are 805 students in each of 51 schools, the total number of students is ...
(805 students/school) × (51 schools) = 41,055 students
_____
We have to assume that all of the students in the county go to county schools. Apparently, we are to ignore the students that are dropouts or homeschooled, or that go to schools not in the county.
