how do you find a perpendicular line?

Question

the line perpendicular to y= -2x+4 and passes through the point (-1,2). Whats the answer?

Answer 1

Gradient of perpendicular = 1/2
Perpendicular passes thro` (-1,2)
Equation of perpendicular is given by:-
y - 2 = (1/2).(x + 1)
2y - 4 = x + 1
2y = x + 5
y = (1/2) x + 5/2

Answer 2

this question gets answered frequently, so here's the general solution.

given y=mx+b, find perpendicular line passing through point (u,v)

the given line has slope m. a perpendicular line will have slope that is the negative reciprocal: -1/m

so the equation of this perpendicular line is
y = -x/m + c
and since the line passes through the point (u,v), then
u and v satisfy this equation so we can plug them in and solve
for the unknown intercept c.
c = v + u/m

therefore the general solution for the specified perpendicular line is:
y = -x/m + (v + u/m)

apply this to your particular problem:
given m = -2, u = -1, v = 2
y = -x/(-2) + 2 + (-1)/(-2)
which simplifies to
y = x/2 + 5/2

Answer 3

First, know that the perpendicular slope is -1/m, where m is the slope of the known line. In this case the perpendicular slope will by 1/2

then you can use the point slope method

(y-2)/(x+1)=1/2

y-2=1/2x+1/2
y=1/2x+5/2

Answer 4

All you have to care about is the slop. Perpendicular line of an equation is always the negative reciprical of the original quation.
for example, y= -2x+4 , slope= -2, its perpendicular line will have the slope of 1/2.
now you got the slope, get a line with it that runs thru point (-1,2)
you will get y=1/2x+"?", plug the number in, 2=1/2(-1)+"?", then you get your answer...

Answer 5

y = mx +b, meaning m= -2. Thus, m perpendicular= -1/-2 or 1/2.
m = (y-2)/(x +1) = 1/2, cross multiplication
(y-2)(2) = (x+1)(1); 2y - 4 = x + 1

Therefore: y = 1/2x + 5/2

Answer 6

All you need to know is that if you know the slope of a given line, then the slope of a line which is perpendicular, is the negative reciprocal to the slope of the given line.

Answer 7

The negative reciprocal of the slope of y= -2x+4

Answer 8

the slope is 1/2, so plug that into y = 1/2 * x + b and use the point (x,y) to find B.

Answer 9

y=0.5x+2.5
perpendicular lines have opposite reciprocal slopes