Question 1155051
the equation is in standard form of ax + by = c
the equation is 12x - 9y = 135
convert to slope intercept form as follows:
add 9y to both sides of the equation and subtract 135 from both sides of the equation to get 12x - 135 = 9y
this is the same as 9y = 12x - 135
divide both sides of the equation by 9 to get:
y = 12/9 * x - 135 / 9
simplify to get y = 4/3 * x - 15
that's your regular equation.
the line perpendicular to it will have a slope that is a negative reciprocal of the slope of the regular equaton.
that makes the slope equal to -3/4
the general form of a slope intercept equation is y = mx + b
m is the slope
b is the y-intercept
when m = -3/4, the equation becomes y = -3/4 * x + b
b can be any value.
for example, when b = 0, the equation of the line perpendicular to the regular line is y = -3/4.
the standard form of the perpendicular line is calculated as shown below.
start with y = -3/4 * x
add -3/4 * x to both sides of the equation to get:
y + 3/4 * x = 0
rearrange the terms so the x term is ahead of they term to get:
3/4 * x + y = 0
multiply both sides of the equation by 4 to get:
3x + 4y = 0
that's the standard form of the equation.
the equations can be graphed.
the graph looks like this.
<img src = "http://theo.x10hosting.com/2020/040201.jpg" alt="$$$" >
the first two equations are equivalent to each other, and the second two equations are equivalent to each other.
each pair is the standard form of the equation and the slope intercept form of the same equation.
you can see that those two forms of each equation draw the same line.