Question

The equation of which of these lines can be derived by drawing one triangle with vertices
(
0
,

0
)
,
(
1
,

0
)
,
and
(
1
,

2
)
and another similar triangle with vertices
(
0
,

0
)
,
(
−
2
,

0
)
,
and
(
−
2
,
−
4
)
?
A.
y
=
−
2
x

B.
y
=
−
1
2
x

C.
y
=
1
2
x

D.
y
=
2
x

Answer 1

D. y = 2x

Reason: The slope from (0,0) to (1,2) is 2/1 = 2, and from (0,0) to (−2,−4) is (−4)/(−2) = 2. So the line through the origin has equation y = 2x.