Question

Select the equations of the lines that are parallel to the line whose equation is y = 3x + 5. There might be more than one answer.

a) 6x + 2y = 12
b) -3x + y = 8
c) 3y = 9x
d) y=-1/3x

Answer 1

Parallel means they have the same slope.
The given equation has a slope of 3. Slope intercept equation: y = mx + b
a. 6x + 2y = 12
Subtract 6x from both sides.
2y = - 6x + 12
Divide both sides by 2.
y = -3x + 6 Not parallel

b. -3x + y = 8
Add 3x to both sides.
y = 3x + 8 Parallel

c. 3y = 9x
Divide both sides by 3
y = 3x Parallel

d. y = -1/3x Not parallel

B and C are parallel