Construct Functions to Model Linear Relationships

How can you write the equation for a linear function if you know only two ordered pairs for the function?

• Use the two ordered pairs to find the slope (m). Then substitute the slope and one set of ordered pairs into y=mx+b to solve for b.

• Use the two ordered pairs to find the y-intercept (b). Then substitute the y-intercept and one set of ordered pairs into y=mx+b to solve for m.

• Use the two ordered pairs to find the value of y. Then substitute the the value of y and one set of ordered pairs into y=mx+b to solve for x.

• Use the two ordered pairs to find the value of x. Then substitute the the value of x and one set of ordered pairs into y=mx+b to solve for y.

A line passes through the points (5, –7.5) and has a y-intercept 10.

Which is a linear function in the form of y = mx + b for this line?

• y = 0.5x + 10

• y = –1.5x + 10

• y = –3.5x + 10

• y = 10x – 3.5

Write a function in the form y=mx+b for the line that passes through the points (2,4) and (6,16)

• y = 3x - 2

• y = 2x + 4

• y = 6x + 16

• y = 2x + 6

Sierra is building a skateboard ramp.

She wants the ramp to have a height, h, of 15 inches and a base length, l, of 54 inches.

Which linear function models the situation?

• y = (5/18)x

• y = (18/5)x

• y = 5x + 18

• y = 18x + 5

Which of the following is in slope-intercept form?

• y=10x-7
• y-5=3(x-1)
• 5x-y=12
• 6x+2y-15=0

Is this function linear or nonlinear?

• Linear
• Nonlinear

Find the slope given the following points: (5,1) and (3,1)

• m=1/4
• m=0
• m=1
• m=undefined

Lee charges $3 for a basket and $2.50 for each pound of fruit picked at the orchard. Write an equation in y = mx + b form for the total cost of x pounds of fruit from the orchard.

• y = 3x + 2.5
• y = 2.50x + 3
• y = 2.50x 
• y = 3x + 2.50

Which equation matches the table?

• y = x + 5
• y = 5x
• y = x - 5
• x = y - 5

What is the slope?

• 1/2
• 2
• 7
• 3