A student uses the division shown to divide, -3x4+15x3-x+5 by x-5 and concludes that x-5 is not a factor of the polynomial. What are the errors?

check the picture below.

well, the angle at the vertex d is clearly not a right-angle, let's check for the one at the vertex f which does look like,   however if it's indeed, that means ef is perpendicular to df, in which case their slopes will be negative reciprocal of each other.

so the negative reciprocal of the slope of ef is 1, however the slope of df is not 1, is 1/2, so nope, they're not perpendicular lines.

(c, 0) i might be wrong so don't put full faith on my answer

56

step-by-step explanation: