3.07 × 10^-4 written in standard form

here are the choices

a. 0.00307

b. 0.000307

c. 30,700

d. 300,700

The point a is at –2 and the point b is at 7. marissa would like to divide this line segment in a 4: 3 ratio, and she would like to use the formula x = (x2 – x1) + x1. what values should she substitute into the formula? a = a + b = x1 = x2 =