Question

Two quantities are related, as shown in the table

x y
2 2
4 5
6 8
8 11

Which equation represents the relationship?

y=3/2x+2
y=3/2x
y=3/2x-1
y=3x+2

Answer 1

y = 3/2x - 1.

I did the test and got it right.

Answer 2

First, take two points, and find the slope.


`\text{Slope } = \frac{ y_2 - y_1 } { x_2 - x_1 } = ( 11 - 2)/( 8 - 2) = ( 9)/( 6) = \boxed{\bf{ (3)/(2)}}`

So now we have an equation:

y = 3/2x + b

Plug in the point (2,2) and solve for b.

2 = (3/2)(2) + b
2 = 3 + b
b = -1

The final equation that represents the relationship is y = 3/2x - 1.