Question

Which of the following is an equation of a line that is parallel to y = 4 x + 9 ? (Choose all correct equations.)
y = 2 x + 9
y = 4 x − 7
12 x − 3 y = 6
− 20 x + 5 y = 45

Answer 1

Answer:

The second, third and fourth are parallel to the given equation

Step-by-step explanation:

In order to determine if the slopes are the same, put all of the equations in slope-intercept form:  y = mx + b.  In order for lines in this form to be parallel, the m values of each have to be the exact same number, in our case, 4.  Equation 2 has a 4 in the m position, just like the given, so that one is easy.  Equation 2 is parallel.

Let's solve the third equation for y:

12x - 3y = 6 so

-3y = -12x + 6 and

y = 4x - 2.  Equation 3 is parallel since there is a 4 in the m position.

Let's solve the fourth equation for y:

-20x + 5y = 45 so

5y = 20x + 45 and

y = 4x + 9.  Equation 4 is also parallel since there is a 4 in the m position.