Phred has already graded 40 papers and he still needs to grade more. write an equation for how many papers he is grading if he continues to grade 4 papers a minute.

y=4x+40

x represents the number of minutes

y is the total

40 because he already graded 40 papers, and 4x because that's how many phred grades times the number of minutes

hello from mrbilldoesmath!

answer:   x (x+6)^2, choice b

discussion:

factor x out of the equation:

x^3 + 12x^2 + 36x = x (x^2 + 12x + 36).

note that 6+6 = 12 and 6*6 = 36 so the above factors into:

x (x+6)^2

which is choice b

you,

mrb