equation of a line perpendicular to the line 3x +7y =21 with a y-intercept of (0, 2).

Question

equation of a line perpendicular to the line 3x +7y =21 with a y-intercept of (0,

2).

Answer 1

Whenever you wish to find the perpendicular of a line whose plane equation is ax+by=c, the first thing is to swap the letters a and b, and make one of them negative, like so: -bx+ay.

Next, equate this to some unknown number, let's say d, which then you plug in the condition for, in this case (0,2). So -b*0+a*2=d, so d=2a.

Now you have the value d and your resulting equation is -bx+ay=d.

Answer 2

1) Find the slope of the present line. In the form ax + by = c slope is -a/b or -3/7 in this case. You also could rearrange the equation alphabetically as y = mx +b with m as the slope.

2) The slope of the perpendicular is -1/m or 7/3 in this case.

3) They nicely gave you the y intercept b = 2 , so you can just write the equation of the perp. line as

y = (7/3)x + 2