<span>8x² - x + x² + 4x - 9x² = 18
3x = 18 | 8x</span>² + x² - 9x² = 0<span>
x = 6 | divide by 3
Answer: x = 6</span>
So you would plug in 0 for a from the beginning since this is numerical slope definition of a derivative
the slope goes by several names
• average rate of change
• rate of change
• deltaY over deltaX
• Δy over Δx
• rise over run
• gradient
• constant of proportionality
however, is the same cat wearing different costumes.
initial value of 3, namely when x = 0, y = 3, so we have the point (0 , 3) and it has a rate or slope of 3/4.

Given:
Four equations in the options.
To find:
The equation which represents a proportional relationship.
Solution:
If y is proportional to x, then


where, k is the constant of proportionality.
In this case if x=0, then y=0. It means the graph of a proportional relationship passes through the origin.
From the given options, only option B, i.e.,
, is of the
, where,
.
So, the equation
represents a proportional relationship.
Therefore, the correct option is B.