Answer:
D. 4.5 kg
Step-by-step explanation:
Hello :
the consecutive room numbers are : n , n+1
n(n+1) =420
n²+n -420 = 0
the discriminant delta = b² - 4ac ( a = 1 and b = 1 and c = - 420
delta = (1)²-4(1)(-420) =1681= 41²
n = (-1 -41)/2 ( refused negatif number)
or
n = (-1+41)/2 =20
<span> the room numbers.are : 20 , 21</span>
X^4+ 3x^3+4x^2-8 | x+2 = x^3+x^2+2x-4
-x^4-2x^3
-----------------------
x^3+4x^2-8
-x^3-2x^2
-------------------------
2x^2-8
-2x^2-4x
--------------
-4x-8
4x+8
----------------------------
/ /
is a factor because (x+2)(x^3+x^2+2x-4)=x^4+3x^3+4x^2-8
Answer:
I think so b is the option
If the two diagonals are
and
, the are of the rhombus is

So, in your case, the area is

The other options are wrong because:
- option A doens't divide by 2, thus getting twice the area of the rhombus
- option B summed the diagonals instead of multiplying them
- option D took the difference of the diagonals.