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Find the point on the line y = -3x + 5 that is closest to the point (2, -2).

a) (-3, 14)
b) (2.3, -1.9)
c) (1.1, 1.7)
d) (2.3, 0.32)

2007-05-30 04:37:28 · 8 answers · asked by Anonymous in Science & Mathematics Mathematics

8 answers

You want the line that is perpendicular to your line that passes through (2,-2): y=(1/3)x-(8/3).
Now find out where the two lines intersect by solving the following equation: -3x+5=(x-8)/3 or -9x+15=x-8
or -10x=-23 or x=2.3; now solve for y: y=-3*(2.3)+5=-1.9.
So your answer is (2.3,-1.9).

2007-05-30 04:43:55 · answer #1 · answered by bruinfan 7 · 1 0

One way to do this, is first find line that has perpendicular
slope of equation. Since slope is -3, the slope perpencilaur to this is -1/-3 = 1/3.
So, equation is y=(1/3)x+b.
Now find the line that has the points (2,-2).
SO, plug in (2,-2), giving you -2=( 1/3)*(2)+b, so b=-2-2/3=-8/3.
SO, the line is y=(1/3)x-8/3.
So, now you just have to find intersection of this line
and y=-3x+5.
So, -3x+5=(1/3)x-8/3, or (-10/3)x=-23/3, so, x=2.3.
So, then just plug this in y=-3x+5, giving you y=-3*2.3+5=-1.9.

So, the answer is b)(2.3,-1.9)

2007-05-30 04:53:34 · answer #2 · answered by yljacktt 5 · 1 0

To find the closest point, draw a line through the point that is perpendicular to the line. Using the point-slope formula:
y-y1=m(x-x1)
Since the two lines are perpendicular, the product of their slopes must be -1. So m=-1/3. Y1 and x1 come from the given point.
y-(-2)=(1/3)(x-2)
y+2=(1/3)x-2/3
y=(1/3)x-8/3
Find the intersection of this line with the first line.
(1/3)x-8/3=y=-3x+5
x-8=-9x+15
10x=23
x=2.3
y=-3*2.3+5=-1.9

So, the answer is (2.3,-1.9), choice (b).

2007-05-30 04:58:19 · answer #3 · answered by Michel_le_Logique 4 · 0 0

B because as u can see 2.3 and -1.9 are the closest to 2 and -2

2007-05-30 04:42:54 · answer #4 · answered by OSUBuckeyes220 1 · 0 1

D. simply by fact Jupiter is made ordinarily of gas and it rotates at as quickly as. D. in the middle of the planet B. ecosystem containing ordinarily hydrogen and helium No, i'm unlikely to make a remark. No, i'm no longer.

2016-10-09 03:23:58 · answer #5 · answered by Anonymous · 0 0

Plug and chug all and see what you get in return.

2007-05-30 04:40:56 · answer #6 · answered by Cool Nerd At Your Service 4 · 0 1

b

2007-05-30 04:44:07 · answer #7 · answered by Jimbob 4 · 0 1

Answer (b)

2007-05-30 04:43:50 · answer #8 · answered by Anonymous · 0 1

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