Writing Linear EquationsMath Review

Question #1

•Write an equation in point-slope form for the line with the given slope that contains the given point.

•Slope = 3•(-4, 2)

Question #1 Answer

•y – 2 = 3(x + 4)

Question #2

•Write the equation of a line in slope-intercept form with slope -4 and passes through the point

(1, -3)

Question #2 Answer

•y = -4x +1

Question #3

•Write an equation of a line in slope-intercept form that passes through the point (2, 1) and

(0, -7)

• Answer: y = 4x - 7

Question #4

•Ally is finishing a scarf at a constant rate. The table shows the number of hours Ally has spent knitting this week and the corresponding number of rows in the scarf.

•Write an equation inslope intercept form that represents this situation.

HOURS ROWS OF KNITTING

2 38

4 44

6 50

Question #4 ANSWER

•y = 3x + 32

Question #5

•A photo lab manager graphed the cost of having photos developed as a function of the number of photos in the order. The graph is a line with slope of 1/10 that passes through (10, 6). Write an equation in slope-intercept form that describes the cost to have photos developed. How much does it cost to have 25 photos developed?

Question #5 ANSWER

•y = (1/10)x + 5•It will cost $7.50 to have 25 photos

developed.

Question #6

•The cost of internet access at a café is a function of time. The costs for 8, 25, and 40 minutes are shown.

•Write an equation in slope-intercept form that represents the function. Then find the cost of surfing the web at the café for one hour.

TIME (min)

8 25 40

Cost ($) 4.36 7.25 9.80

Question #6 ANSWER

• y = 0.17x + 3•It would cost $13.20 to surf the web at

the café for one hour.

Question #7

•Karen hired an electrician for a $45 consultation fee plus an hourly rate. The job took 3.5 hours and cost $150.

•Write an equation in slope-intercept form that represents this situation.

•What does the slope represent in this situation?

•What does the y-intercept represent in this situation?

Question #7 ANSWER

•Equation: y = 30x + 45•The slope represents the electrician’s

hourly rate. (In other words, how much he charges per hour)

•And, the y-intercept represents the electrician’s consultation fee =)