
Emily W. answered 11/19/21
High School and College Level Math and Science in Central Florida
First, we will write the equation of the parallel line in slope intercept form y=mx+b so that we can clearly see the slope and y intercept:
2x-3y = 9 subtract 2x from both sides
-2x -2x
-3y = -2x + 9 divide both sides by -3
y = -2x/-3 + 9/-3
-2/-3 simplifies to 2/3 because the negative signs cancel out, and 9/-3 simplifies to -3. The equation of the parallel line in the form y=mx+b is
y= 2/3 x -3
The only piece of information that we need from this equation is the slope, which is 2/3.
**PARALLEL LINES HAVE THE SAME SLOPE**
To find the equation for our line, we get to use a slope of 2/3 because parallel lines have the same slope. We have the “m” of our equation and only need to find the y intercept “b”. We can plug in the slope as m= 2/3 and our given ordered pair (4,-1), where x=4 and y=-1, to find b.
y = m x + b
-1 = 2/3*4 + b. Multiply 4 * 2/3 (the 4 only multiplies with the top number)
-1 = 8/3 + b. Subtract 8/3 from both sides to get b alone
-1 -8/3 = b. The common denominator between -1/1 and 8/3 is 3. To reach 3, -1/1 needs to multiply by 3 on top and bottom to become -3/3, and 8/3 can stay the same (it’s already at 3)
-3/3 - 8/3 = b (only the top combines and the bottom stays the same)
-11/3=b
Now that we have m = 2/3 and b = -11/3, we can put the final equation together:
y = 2/3 x - 11/3