Say whether each of the following equations give a straight line or not. Give a reason for each answer.

a) [[$ y = x + 6 $]]

This equation is isn't a line, because

b) [[$ 3y = 3 x \: – 4 $]]

This equation is isn't a line, because

c) [[$ y = 2x^2 + 4x $]]

This equation is isn't a line, because

d) [[$ y = x^2 + y^2 $]]

This equation is isn't a line, because

e) [[$ y = 4 \: – x = 5 + 2y $]]

This equation is isn't a line, because

f) [[$ \displaystyle\frac {x} {3} + \displaystyle\frac {y} {3} = 2 $]]

This equation is isn't a line, because

g) [[$ \displaystyle\frac {3} {x} + \displaystyle\frac {3} {y} = 2 $]]

This equation is isn't a line, because