Problems from Quotient of polynomials

Calculate the following polynomial division $$\dfrac{x^4-2x+3}{x^2-2}$$

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Development:

We complete and we design the initial table

$$x^4$$ $$0$$ $$0$$ $$-2x$$ $$3$$ $$x^2-2$$

Step 1:

$$\dfrac{x^4}{x^2}=x^2$$

$$x^2\cdot(x^2-2)=x^4-2x^2$$

$$x^4$$ $$0$$ $$0$$ $$-2x$$ $$3$$ $$x^2-2$$
$$-x^4$$ $$0$$ $$+2x^2$$ $$0$$ $$0$$ $$x^2$$
$$0$$ $$0$$ $$+2x^2$$ $$-2x$$ $$3$$  

Step 2:

$$\dfrac{2x^2}{x^2}=2$$

$$2\cdot(x^2-2)=2x^2-4$$

$$x^4$$ $$0$$ $$0$$ $$-2x$$ $$3$$ $$x^2-2$$
$$-x^4$$ $$0$$ $$+2x^2$$ $$0$$ $$0$$ $$x^2+2$$
$$0$$ $$0$$ $$+2x^2$$ $$-2x$$ $$3$$  
    $$-2x^2$$ $$0$$ $$+4$$  
    $$0$$ $$-2x$$ $$7$$  

The process ends here because:

degree$$(-2x+7)=1 < 2=$$degree$$(x^2-2)$$

Solution:

Quotient: $$x^2+2$$

Reminder: $$-2x+7$$

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Consider the following polynomials:

$$p(x)=-x^3+x$$

$$q(x)=2x^3-x-3$$

$$r(x)=-x+1$$

Do the following operation: $$(r(x)+q(x))\cdot p(x)$$

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Development:

First we do the addition,

  r(x) q(x) r(x)+q(x)
degree 0 $$1$$ $$-3$$ $$-2$$
degree 1 $$-x$$ $$-x$$ $$-2x$$
degree 2 $$0$$ $$0$$ $$0$$
degree 3 $$0$$ $$2x^3$$ $$2x^3$$

$$r(x)+q(x)=2x^3-2x-2$$

Then, the product by the monomials of $$p(x)$$,

$$x\cdot(r(x)+q(x))=x\cdot(2x^3-2x-2)=2x^4-2x^2-2x$$

$$-x^3\cdot(r(x)+q(x))=-x^3\cdot(2x^3-2x-2)=-x^6+2x^4+2x^3$$

Solution:

We join both polynomials and make groups of similar terms:

$$(r(x)+q(x))\cdot p(x)=(2x^4-2x^2-2x)+(-x^6+2x^4+2x^3)=$$

$$=-x^6+4x^4+2x^3-2x^2-2x$$

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