Graphing Problems?

Question

Line l goes throught the point (2,–4) and is perpendicular to the line through (–6, 5) and (–3, –2). Find the slope of l. Match your result to the correct answer below.
A) 37
B) 73
C) -73
D) 0

Which of the following equations represents a line l that goes through (2,1) and has slope –3?
A) y = –3x + 6
B) y = –3x + 3
C) y = 3x – 7
D) y = –3x + 7

. Find the equation (in standard form) of the line through (5, –5) and (8, 1). Match your result to the correct answer below.
A) 2x + y = 15
B) x – 2y = 30
C) 2x – y = 15
D) 230xy−=215

Answer 1

1) find the slope of the line using the 2 points and take its negative inverse to get the slope of the line you want.
5-(-2) / [-6 - (-3)]
7 / -3 = -7/3
slope of line (I)= 3/7

Choice A



2) General line equation is:
y = mx + b
plug in your point (2,1) and solve for b
1 = 2(-3) + b
b = 7
Choice D is the equation of the line.

3)find the slope
slope = [-5 -1] / [5-8]
slope = -6/-3 = 2
General line equation is
y = mx + b
plug i slope of 2 and a given point:

1 = 2(8) + b
solve for b
b= -15
y = 2x - 15
swap the y and 15 around to get:
choice C

Answer 2

1 a 3/7
2 d
3 c