Which function rule represents the input-output table?

x | y
1 | 8
2 | 11
3 | 14
4 | 17

A: h(x)=-3x-5
B: h(x)=3x+5
C: h(x)=-3x+5
D: h(x)=3x-5

2 answers

11 - 8 = 3

14 - 11 = 3

17 - 14 = 3

If x increases by increases by 1, y increases by increases by 3, so this is a linear function.

Slope for any linear function is:

m = ( yA - yB ) / ( xA - xB )

where:

xA, yA is first point

xB, yB is second point

You can choose any two points e.g.

xA = 1 , yA = 8

xB = 3 , yB = 14

m = ( yA - yB ) / ( xA - xB ) = ( 14 - 8 ) / ( 3 - 1 ) = 6 / 2 = 3

The slope-intercept form of a straight line:

y = m x + b

In this case:

y = 3 x + b

Select any point to calculate the value of b.

e.g.

x = 4 , y = 17

y = 3 x + b

17 = 3 ∙ 4 + b

17 = 12 + b

Subtract 12 to both sides

5 = b

b = 5

So:

y = m x + b

y = 3 x + 5

Answer B
@Bosnian THANK YOU!!!