Need asap- five questions on scientific notation

combine the like terms in the expression.

a. -12x^4 + 7x^4 + 6x^4

b. 2r + 7r + 16x

c. 30z^8 + 7z^8 + 8z

d. 15a^2 - 15b^2 + 13a^2 - b^2

e. 7x^2 - 82x + 12x^2 - 2x

Figure lmno is located at l (1, 1), m (4, 4), n (7, 1), and o (4, −2). use coordinate geometry to best classify quadrilateral lmno.

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?

Assume that 1400 births are randomly selected and 1378 of the births are girls. use subjective judgment to describe the number of girls as significantly high, significantly low, or neither significantly low nor significantly high. choose the correct answer below. a. the number of girls is neither significantly low nor significantly high. b. the number of girls is significantly high. c. the number of girls is significantly low. d. it is impossible to make a judgment with the given information.