Answer:
y = 5
x = 10
Step-by-step explanation:
-4(2y) + 11y
-8y + 11y = 15
3y = 15
/ 3 /3
y = 5
x = 10
Answer:
a1 = 4
a2= -2
a3 = -8
a4= -14
a5= -20
Step-by-step explanation:
a12= a1 + 11d
-62 = 4 + 11d
-62-4 = 11d
-66= 11d
d = 
= -6
a1 = 4
a2 = 4 - 6 = -2
a3 = 4 - (6×2) = -8
a4 = 4 - (6×3) = -14
a5 = 4 - (6×4) = -20
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!
