Question

These two lines are parallel. Write an equation for each.

УТ
y
5
4
3
N
1
2 3 4 5 6
7
8
9
10 11 x
1
1
N
-2
-3
4 (0.-3.2)
-5

Answer 1

• y = 0.8x
• y = 0.8x -3.2

Explanation:

Each line has a rise of 4 units for each run of 5 units to the right. That makes the slope be ...

m = rise/run = 4/5 = 0.8

The top line shows a simple proportional relationship, so its equation is ...

y = 0.8x . . . . . top line

The bottom line has the same slope and a y-intercept of -3.2. Its slope-intercept form equation is ...

y = mx +b . . . . . line with slope m and y-intercept b

y = 0.8x -3.2 . . . . bottom line