Which of the following has a constant of proportionality of 2? A) y = 2x B) y = x + 2 C) 2y = x D) y + 2 = 2x
2 answers:
The correct answer is A.
You have direct variation if x and y are modeled by the equation
In this case, m is the constant of proportionality. So, if the constant has to be 2, the equation becomes
A side note: Actually, option C has a constant of proportionality of two as well, except the roles of x and y are interchanged. I chose option A because usually you want the y = mx form, but the names of the variables are obviously meaningless.
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Length of rectangle is 1 unit
<u>Solution: </u>
Given that
Length of a rectangle is width minus 8 units.
Area of rectangle = 9 square units
Need to calculate the length of rectangle.
Let us assume width of rectangle = x
As Length is width minus 8,
Length of the rectangle = x – 8
As given that area of rectangle = 9 square units
On solving above quadratic equation for x, we get
When
When
As width cannot be negative, so considering x = 9
Hence, Length of rectangle is 1 unit.