Question

-21+71x-24x^3-31x^2 by 3-8x
long divison method ​

Answer 1

We have to divide -21+71x-24x³-31x² by 3-8x.

We can write -21+71x-24x³-31x² as -24x³-31x²+71x-21.

Also, we can write 3-8x as -8x+3.

$\boxed{\begin{array}{l | n | r}\sf - 8x + 3&\sf - 24 {x}^{3} - 31 {x}^{2} + 71x - 21 &\sf 3 {x}^{2} + 5x - 7\\ &\sf - 24 {x}^{3} + 9 {x}^{2} \\ & ( + )\quad( - )\\&\rule{60}{0.8}\\&\sf \qquad 0 \: - \: 40 {x}^{2} + 71x \\ &\sf \qquad\quad-\:40 {x}^{2} + 15x\\ & \qquad \: \: \: \: ( + ) \: \: \: \:\:( - )\\& \qquad\quad\rule{60}{0.8}\\&\qquad\quad \quad\sf 0 + 56x - 21\\ &\sf\qquad \: \: \: \qquad\quad\sf 56x - 21\\&\qquad\qquad \: (-)\:\: \: \: \: ( + )\\& \qquad\qquad\qquad\rule{50}{0.8}\\ &\sf\qquad\qquad \qquad \qquad\quad0\end{array}}$

Answer :

$\large \bf 3 {x}^{2} + 5x - 7$