Answer:
y = 
Step-by-step explanation:
y = log 5 2x
inverse ------> y=x
x = log 5 2y

y = 
If the length of a rectangle is a two-digit number with identical digits and the width is 1/10 the length and the perimeter is 2 times the area of the rectangle, what is the the length and the width
Solution:
Let the length of rectangle=x
Width of rectangle=x/10
Perimeter is 2(Length+Width)
= 2(x+x/10)
Area of Rectangle= Length* Width=x*x/10
As, Perimeter=2(Area)
So,2(x+x/10)=2(x*x/10)
Multiplying the equation with 10, we get,
2(10x+x)=2x²
Adding Like terms, 10x+x=11x
2(11x)=2x^2
22x=2x²
2x²-22x=0
2x(x-11)=0
By Zero Product property, either x=0
or, x-11=0
or, x=11
So, Width=x/10=11/10=1.1
Checking:
So, Perimeter=2(Length +Width)=2(11+1.1)=2*(12.1)=24.2
Area=Length*Width=11*1.1=12.1
Hence, Perimeter= 2 Area
As,24.2=2*12.1=24.2
So, Perimeter=2 Area
So, Answer:Length of Rectangle=11 units
Width of Rectangle=1.1 units
The last one is the answer
You can solve this problem by applying the proccedure below:
You have:
a) 18/21=2/3
18x3/21x2
36≠42 (2/3 is not proportinal to 18/21).
b)18/21=30/35
18x35/21x30
630=630 (30/35 is proportional to 18/21)
c)18/21=36/48
18x48/21x36
864≠756 (36/48<span> is</span><span> not proportinal to 18/21)
</span>
d)18/21=1/3
18x3/21x1
54≠21 (<span> 1/3 is</span><span> not proportinal to 18/21)
</span>
Therefore, you can conclude that the correct option is: B.30/35