<h3>
Answer:</h3>
- -100x +100; 3
- 5x +81; 162
<h3>
Step-by-step explanation:</h3>
The distributive property is your friend. It tells you ...
a(b + c) = ab + ac
It can also be used to simplify the product of binomials (or other polynomials).
(a +b)^2 = (a +b)(a +b) = a(a +b) + b(a +b) = a^2 +ab +ab +b^2
(a +b)^2 = a^2 +2ab + b^2 . . . . . . . worth remembering
1. (x -10)^2 -x(x +80) = (x^2 -20x +100) +(-x^2 -80x)
= -100x +100 . . . . . . simplified form
For the purposes of calculation, it can be easier to factor out 100:
= 100 (1 -x)
Then for x = 0.97
= 100(1 -0.97) = 100(0.03) = 3
___
2. (2x +9)^2 -x(4x +31) = (4x^2 +36x +81) -4x^2 -31x = 5x +81
For x = 16.2, this is ...
5(16.2) +81 = 81 +81 = 162
_____
The purpose of the attachment is to show the evaluation is correct.
Notice the picture below
now, we know their perimeter are the same for both
thus 4(a+4) = 6a
solve for "a"
Answer: C. 150 km²
<u>Step-by-step explanation:</u>
Use similar triangle proportion to find x:

If you pay attention i believe it would be 340 so shes right give her brainliest
Answer:
number of terms=9
Step-by-step explanation:
![t_{1}=6\\t_{5}=18\\\\t_{n}=t_{1}+(n-1)d\\18=6+(5-1)d\\18-6=4d\\4d=12\\d=12/4=3\\s_{n}=162\\s_{n}=\frac{n}{2}[2t_{1}+(n-1)d]\\162=\frac{n}{2}[2(6)+(n-1)3]\\162 \times 2=n(12+3n-3)\\324=n(3n+9)\\3n^2+9n-324=0\\n^2+3n-108=0\\n^2+12n-9n-108=0\\n(n+12)-9(n+12)=0\\(n+12)(n-9)=0\\n=-12,9\\n=-12 (rejected)](https://tex.z-dn.net/?f=t_%7B1%7D%3D6%5C%5Ct_%7B5%7D%3D18%5C%5C%5C%5Ct_%7Bn%7D%3Dt_%7B1%7D%2B%28n-1%29d%5C%5C18%3D6%2B%285-1%29d%5C%5C18-6%3D4d%5C%5C4d%3D12%5C%5Cd%3D12%2F4%3D3%5C%5Cs_%7Bn%7D%3D162%5C%5Cs_%7Bn%7D%3D%5Cfrac%7Bn%7D%7B2%7D%5B2t_%7B1%7D%2B%28n-1%29d%5D%5C%5C162%3D%5Cfrac%7Bn%7D%7B2%7D%5B2%286%29%2B%28n-1%293%5D%5C%5C162%20%5Ctimes%202%3Dn%2812%2B3n-3%29%5C%5C324%3Dn%283n%2B9%29%5C%5C3n%5E2%2B9n-324%3D0%5C%5Cn%5E2%2B3n-108%3D0%5C%5Cn%5E2%2B12n-9n-108%3D0%5C%5Cn%28n%2B12%29-9%28n%2B12%29%3D0%5C%5C%28n%2B12%29%28n-9%29%3D0%5C%5Cn%3D-12%2C9%5C%5Cn%3D-12%20%28rejected%29)
as number of terms can't be negative.