Answer:
a). 
b). V = 15 units
Step-by-step explanation:
Focal length F of a lens made by combining two lenses of different focal lengths U and V will be,

A). By solving the given formula,



B). If F = 6 and U = 10 then we have to find the value of V.
By substituting the given values in the formula,


V = 15 units
Therefore, focal length (V) of the lens = 15 units
Short answer: C
Let's start with the pen.
The length is x
The width is 3 more.= x + 3
Perimeter of the pen = 2L + 2W
P = 2 L + 2W
P = 2*x + 2(x + 3)
P = 2x + 2x + 6
P = 4x + 6. Leave that for now.
Area of the pen without the doghouse = x(x + 3)
Area of the pen without the doghouse = x^2 + 3x
Area with the doghouse x^2 + 3x - y = 178 (that's his running around space.
Go to the dog house for a Moment
The perimeter of the doghouse and the area are equal and we are told to make them both y.
Area = y
Perimeter = y
Combined facts.
The perimeter of the Pen is three times larger than that of the dog house.
4x + 6 = 3y
The area of the Pen - The area of the doghouse = 178
x^2 + 3x - y = 178
Now what happens is that you have to juggle these two equations so they look like your answer
x^2 + 3x - y = 178
4x + 6 = 3y Subtract 3y from both sides.
4x - 3y + 6 = 0 Subtract 6 from both sides.
4x - 3y = - 6
Answer C
Answer:3/4
Step-by-step explanation: