How do you add, subtract, multiply, and divide numbers written in scientific notation?

Can someone me and do the problem plz so i can understand it more better

Which shows one way to determine the factors of 4x3 + x2 – 8x – 2 by grouping?

Which statements are true? check all that apply. the line x = 0 is perpendicular to the line y = –3. all lines that are parallel to the y-axis are vertical lines. all lines that are perpendicular to the x-axis have a slope of 0. the equation of the line parallel to the x-axis that passes through the point (2, –6) is x = 2. the equation of the line perpendicular to the y-axis that passes through the point (–5, 1) is y = 1.