Which of the following has a graph that is a straight line? (4 points)
Equation 1: y = 4x3 + 6
Equation 2: y = 5x − 4.5
Equation 3: y2 = x − 1
Equation 4: y = 2x2 + 6
Equation 1: y = 4x3 + 6
Equation 2: y = 5x − 4.5
Equation 3: y2 = x − 1
Equation 4: y = 2x2 + 6