OK the next step is to multiply 3r -1 by -7r this gives us -21r^2 + 7r and we write it below -21r^2 + 25r and subtract This gives us 18r and we bring down the -6 to give 18r - 6
Finally we divide 18r by -3r to give -6 then add - 6 to the r^2 - 7r on the top then multiply -3r - 1 by -6 to give 18r - 6 subtraction then leaves nothing.
