2. Without using a graphing calculator, identify all of the following equations that graph as straight lines. Explain how you decide.
a. \( y = 3 x \) e. \( y = \frac { 1 } { x } + 3 \)
b. \( y = 2 x ^ { 2 } - 2 \) f. \( y = 7 - x \)
c. \( y = x - 5 \) g. \( y = \frac { 1 } { 2 x + 3 } \)
d. \( y = \sqrt { 2 x + 4 } \) h. \( y = x ^ { 3 }\)