Write the standard form of the line passing through the point (-1,1) and perpendicular to the line 4x-7y=35???

Question

It's Multiple choice.

A) 7x=4y=-3
B) 4x-7y=-3
C) -7x-4y=-3
D) 4x=7y=3

Please explain how to do this.

Answer 1

To find a line perpendicular to another, the perpendicular line is equal to the negative reciprocal of the gradient of the first line.

To find the equation of the line find the negative reciprocal of the gradient and then substitute the values in.

Answer 2

Read through the chapter. But think about this.... If you have a line of slope m it intercepts y and x axis somewhere. Now if you draw a line perpendicular to that you'll notice that the slope of your new line will be negative if the first was positive or positive if the first was negative. In any case. Now you need to figure out what the new line slope is and figure out where it intercepts the x and y axis. Remember a line equation is:
y = mx + b (m = slope, b = y intercept)
The formula for finding the perpendicular line is:
y = (-1/m)x +b
The m is the same as the first line but the b will be different so to find it you just need to use the points they gave you (-1,1)
1 = (-1/m) (-1) + b solve for b.

Basically the slope of a perpendicular line is the negative inverse of the first line. And the intercept b will be found using given info on that new line.

Lengthy explaination but I don't like given people answers.

Hope this helps and good luck.

Answer 3

To get an equation for a line, you either need two points on the line or one point and the slope. Here, you have the second one.

Consider the line 4x - 7y = 35. We need the slope. The easiest way to get it is to put it into slope/intercept form - i.e. solve it for y.

4x - 7y = 35

-7y = -4x + 35

7y = 4x - 35

y = (4/7)x - 5

So the slope is 4/7. The slope of a line perpendicular to this one would be -7/4.

So, we want a line of slope -7/4 passing through (-1, 1). Use the point/slope form

y - y1 = m(x - x1)

y - 1 = (-7/4)(x + 1)

Rearrange it to standard form:

4y - 4 = -7x - 7

7x + 4y = -3

So it's A.

Answer 4

hence of truth the coordinates are X and Y placed both contained in the position it says x and the -3 the position it says Y. Then it is going to be -3=4(2)+7 -3=8+7 -3 isn't equivalent to 15 So then it will be 3 over 15 becasue in perpendicular kind it switxhes. So then you simplify and get 5. favor this helped!!

Answer 5

The big question is - can you explain it in school tomorrow if given different numbers?