Question

encontre a equaçao reduzida da reta que passa pelos pontos:

 

a) (1,2) e (2,5)

b) (-1,2) e (-2,1)

c) (0,3) e (-1,4)

d) (-3,-2) e (2,-3)

Answer 1

(x,y) (xo,yo)

m=(y-yo)/(x-xo)

y-yo=m(x-xo)

a)

m=(2-5)/(1-2)

m=-3/-1

m=3

y-5=3(x-2)

y-5=3x-6

y=3x-1

 

b)

m=(2-1)/(-1+2)

m=1/1

m=1

y-1=x+2

y=x+3

 

c)

m=(3-4)/(0+1)

m=-1

y-4=-x+1

y=-x+5

 

d)

m=(-2+3)/(-3-2)

m=1/(-5)

y+3=-1/5(x-2)

y+3=-x/5+2/5

y=-x/5-13/5

y=(x-13)/5

Answer 2

a)

| x   y   1 |

| 1  2   1 |=0

| 2  5   1|

 

2x+2y+5-4-y-5x=0

-3x+y+1=0

y=3x-1

 

b)

|   x   y   1 |

| -1  2    1|=0

| -2  1    1|

 

2x-2y-1+4+y-x=0

x-y+3=0

y=x+3

 

c)

|  x   y   1 |

|  0  3   1 |=0

| -1  4   1|

 

3x-y+3-4x=0

-x-y+3=0

y=-x+3

 

d)

|  x     y   1 |

| -3  -2  1 |=0

|  2   -3  1|

 

-2x+2y+9+4+3y+3x=0

x+5y+13=0

y=-x/5-13/5