Math Problem Statement

Factorizations and simplifications of algebraic expressions, including cube-related polynomials and square root rationalizations.

Solution

Let's break down and solve the exercises from the image you uploaded:

Factorizations:

  1. A(x) = x³ - 8
    This is a difference of cubes:
    x38=(x2)(x2+2x+4)x^3 - 8 = (x - 2)(x^2 + 2x + 4)
  2. B(x) = x³ - 8 - 4(6x² - 4) + 5x - 10
    Simplify the expression:
    B(x)=x3824x2+16+5x10B(x) = x^3 - 8 - 24x^2 + 16 + 5x - 10 B(x)=x324x2+5x2B(x) = x^3 - 24x^2 + 5x - 2
  3. C(x) = x³ + 27
    This is a sum of cubes:
    x3+27=(x+3)(x23x+9)x^3 + 27 = (x + 3)(x^2 - 3x + 9)
  4. D(x) = x³ + 27 + 3(x² - 9) + x - 3
    Simplify:
    D(x)=x3+27+3x227+x3D(x) = x^3 + 27 + 3x^2 - 27 + x - 3 D(x)=x3+3x2+x3D(x) = x^3 + 3x^2 + x - 3

1) a) Calculations:

  • A:
    Expression to simplify:
    A=(b2)2535[1]A = \left( \frac{b}{2} \right)^{-2} - \frac{\sqrt{5}}{3\sqrt{5}} \cdot [-1] The first part:
    (b2)2=(2b)2=4b2\left( \frac{b}{2} \right)^{-2} = \left( \frac{2}{b} \right)^2 = \frac{4}{b^2} The second part simplifies to:
    535=13\frac{\sqrt{5}}{3\sqrt{5}} = \frac{1}{3} Thus,
    A=4b2(13)=4b2+13A = \frac{4}{b^2} - \left(-\frac{1}{3}\right) = \frac{4}{b^2} + \frac{1}{3}

  • B:
    Expression:
    B=Λ35Λ5+5B = \frac{\Lambda}{3\sqrt{5}} - \frac{\Lambda}{5 + \sqrt{5}}

1) b) Show that:

35+125+5N\frac{3}{\sqrt{5}} + \frac{12}{5 + \sqrt{5}} \in \mathbb{N} First, rationalize both terms. For the first term:
3555=355\frac{3}{\sqrt{5}} \cdot \frac{\sqrt{5}}{\sqrt{5}} = \frac{3\sqrt{5}}{5} For the second term:
125+55555=12(55)(5+5)(55)=12(55)255=12(55)20=3(55)5\frac{12}{5 + \sqrt{5}} \cdot \frac{5 - \sqrt{5}}{5 - \sqrt{5}} = \frac{12(5 - \sqrt{5})}{(5 + \sqrt{5})(5 - \sqrt{5})} = \frac{12(5 - \sqrt{5})}{25 - 5} = \frac{12(5 - \sqrt{5})}{20} = \frac{3(5 - \sqrt{5})}{5} Adding both terms:
355+3(55)5=355+15355=155=3\frac{3\sqrt{5}}{5} + \frac{3(5 - \sqrt{5})}{5} = \frac{3\sqrt{5}}{5} + \frac{15 - 3\sqrt{5}}{5} = \frac{15}{5} = 3 Hence, 3N3 \in \mathbb{N}, so the result holds.

2) Develop and simplify (23)4(2 \cdot \sqrt{3})^4:

(23)4=(24)(34)=169=144(2\sqrt{3})^4 = (2^4)(\sqrt{3}^4) = 16 \cdot 9 = 144

Now, simplify (2+3)2(2 + \sqrt{3})^2: (2+3)2=22+2(2)(3)+(3)2=4+43+3=7+43(2 + \sqrt{3})^2 = 2^2 + 2(2)(\sqrt{3}) + (\sqrt{3})^2 = 4 + 4\sqrt{3} + 3 = 7 + 4\sqrt{3}

3) Factorize Φ=3x(x1)(x21)\Phi = 3x(x - 1) - (x^2 - 1):

Expand:
Φ=3x(x1)(x21)=3x23xx2+1\Phi = 3x(x - 1) - (x^2 - 1) = 3x^2 - 3x - x^2 + 1 Simplify:
Φ=2x23x+1\Phi = 2x^2 - 3x + 1 Now, factor the quadratic:
Φ=(2x1)(x1)\Phi = (2x - 1)(x - 1)

4) Given that aa and bb are non-zero real numbers, prove that:

(ab)nbn+1an=b\left( \frac{a}{b} \right)^n b^{n + 1} a^{-n} = b The left-hand side simplifies to:
(ab)nbn+1an=anbnbn+11an=bn+1bn=b\left( \frac{a}{b} \right)^n b^{n + 1} a^{-n} = \frac{a^n}{b^n} \cdot b^{n + 1} \cdot \frac{1}{a^n} = \frac{b^{n + 1}}{b^n} = b Hence, the equation is true.


Would you like more details on any step? Here are five related questions to practice:

  1. How can you factor higher powers of polynomials using special formulas?
  2. What are the steps to rationalize fractions with square roots in the denominator?
  3. Can you prove the identity for simplifying (a/b)nbn+1an(a/b)^n b^{n+1} a^{-n}?
  4. How would you apply the distributive property to expand binomials like (x+y)n(x + y)^n?
  5. What methods can you use to factorize polynomials of higher degrees?

Tip: Always simplify square root expressions before proceeding with operations, such as addition or multiplication!

Ask a new question for Free

By Image

Drop file here or Click Here to upload

Math Problem Analysis

Mathematical Concepts

Algebra
Factorization
Cubic Equations
Radicals
Rationalization of Fractions
Quadratic Equations

Formulas

Difference of cubes: a^3 - b^3 = (a - b)(a^2 + ab + b^2)
Sum of cubes: a^3 + b^3 = (a + b)(a^2 - ab + b^2)
Rationalizing square roots
Quadratic equation factorization

Theorems

Cubic and quadratic factorization theorems
Properties of square roots and rationalization

Suitable Grade Level

Grades 10-12