Thread: Express algebraically

Express each of the following algebraically:

a. a vertical line 2 units to the left of the y-axis
b. a line parallel to the x-axis and contains the point (3,5)
c. a set of points where the abscissa is always twice the ordinate.
d. the set of pints in the fourth quadrant

help please, thanks!

Originally Posted by reiward

Express each of the following algebraically:

a. a vertical line 2 units to the left of the y-axis
b. a line parallel to the x-axis and contains the point (3,5)
c. a set of points where the abscissa is always twice the ordinate.
d. the set of pints in the fourth quadrant

help please, thanks!

a. x = -2
b. y = 5
c. + c (c = constant)
d. ......(x, -y)...?

a) x = -2


b) a line that is parallel to x axis and goes through (3,5) also goes through (4,5) and (5,5).. etc. any x is good as long as y coordinate remains 5.

so y = 5
covers them all x-es.

c)
abscissa = x-axis
ordinate = y-axis

x = 2y
or better
y = x/2

d) 4th quadrant is the lower right one.
in the 4th quadrant x are positive and y are negative.
so x > 0
and y < 0.
M = {x,y | (x>0) ^ (y<0)}