Ian multiplied a number by 5 he then multiplied that product by 2 what digit is in the ones place of the final product

Which approach to the theory-and-research cycle does the following sequence reflect: (1) specific observations suggest generalizations, (2) generalizations produce a tentative theory, (3) the theory is tested through the formation of hypotheses, and (4) hypotheses may provide suggestions for additional observations?

Solve the given system of equations. 2y= -x+9 , 3x-6= -15

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