A) The line y = 4 meets the line 2x + y = 8 at the point A Fins the co-ordinates of A

b) The line 3x + y = 18 meets the x axis at the point B

Find the co-ordiantes of B

c) (i) Find the co-ordiantes of the mid-point M of the line joining A to B

(ii) Find the equation of the line through M parallel to 3x + y =18

answers :

a.

coordinates of A are (2,4)

b.

coordinates of B are (6,0)

i.

(4,2) is the midpoint

ii.

y = -3x + 18 is the parallel line

Step-by-step explanation:

a.

if two things are equal to the same thing then they are equal to each other

y = 4

2x + y = 8 is y = -2x +8 so

-2x +8 = 4

-2x = -4

x = 2

coordinates of A are (2,4)

b.

if two things are equal to the same thing then they are equal to each other

y=0

3x+y=18 is y = -3x+18 so

-3x+18=0

x = 6

coordinates of B are (6,0)

midpoint formula is

(X1+X2)/2 , (Y1+Y2)/2

(2,4) (6,0)

(X1+X2)/2 , (Y1+Y2)/2

(2+6)/2 , (4+0)/2

(4,2) is the midpoint

parallel line has the same x value

so for a line parallel to 3x+y=18 or y = -3x+18

the parallel line would be

y = -3x

point slope formula

point slope formulay - y1 = m (x - x1)

3x+y=18 or y = -3x+18 was 6,0 at y = 0

y - y1 = m (x - x1)

y - 0 = m (x - x1)

since it's a parallel line the m has to be the same

(6,0)

y - 0 = -3 (x - 6)

y = -3x + 18 is the parallel line