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Question

Simplify 5x(x + 2) + 4x

A.5x 2+ 10

B.9x + 10

C.5x 2- 14x

D.5x 2+ 14x

The correct answer is

D

Simplifying Algebraic Expressions

The question asks us to simplify the algebraic expression: \(5x(x + 2) + 4x\).

To simplify this expression, we need to follow the standard rules of algebra, which involve the distributive property and combining like terms.

Applying the Distributive Property

First, we apply the distributive property to the term \(5x(x + 2)\). The distributive property states that \(a(b+c) = ab + ac\). In our case, \(a = 5x\), \(b = x\), and \(c = 2\).

So, \(5x(x + 2)\) becomes:

\(5x \times x + 5x \times 2\)

This simplifies to:

\(5x^2 + 10x\)

Combining Like Terms

Now we substitute this back into the original expression:

\(5x^2 + 10x + 4x\)

Next, we combine the like terms. Like terms are terms that have the same variables raised to the same power. In this expression, \(10x\) and \(4x\) are like terms because they both have the variable \(x\) raised to the power of 1.

We combine them by adding their coefficients:

\(10x + 4x = (10 + 4)x = 14x\)

The term \(5x^2\) is not a like term with \(10x\) or \(4x\), so it remains as is.

Putting it all together, the simplified expression is:

\(5x^2 + 14x\)

Final Simplified Expression

The simplified form of \(5x(x + 2) + 4x\) is \(5x^2 + 14x\).

Let's compare this result with the given options:

Option Expression
A \(5x^2 + 10\)
B \(9x + 10\)
C \(5x^2 - 14x\)
D \(5x^2 + 14x\)

Our simplified expression \(5x^2 + 14x\) matches option D.

Steps to Simplify

  • Distribute the term outside the parenthesis: \(5x(x+2) = 5x \times x + 5x \times 2 = 5x^2 + 10x\).
  • Rewrite the expression: \(5x^2 + 10x + 4x\).
  • Combine like terms (\(10x\) and \(4x\)): \(10x + 4x = 14x\).
  • The simplified expression is \(5x^2 + 14x\).

Revision Table: Simplifying Algebraic Expressions

Concept Description Example
Distributive Property Multiply a term outside parentheses by each term inside. \(a(b+c) = ab + ac\)
Like Terms Terms with the same variable(s) raised to the same power(s). \(3x\) and \(7x\); \(2y^2\) and \(-5y^2\)
Combining Like Terms Add or subtract the coefficients of like terms. \(3x + 7x = (3+7)x = 10x\)

Additional Information: Polynomials

Algebraic expressions like \(5x^2 + 14x\) are examples of polynomials. A polynomial is an expression consisting of variables and coefficients, using only the operations of addition, subtraction, multiplication, and non-negative integer exponents of variables.

  • Term: A single number, variable, or the product of numbers and variables (e.g., \(5x^2\), \(10x\), \(4x\)).
  • Coefficient: The numerical factor of a term (e.g., 5 in \(5x^2\), 10 in \(10x\), 4 in \(4x\)).
  • Variable: A symbol representing an unknown value (e.g., \(x\)).
  • Exponent: A number that indicates how many times the base is multiplied by itself (e.g., 2 in \(x^2\)).

Simplifying polynomials involves combining like terms to reduce the expression to its simplest form.

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Important Questions from Linear Equation in 1 Variable

  1. If a school of fish weighs 3 kg and each fish in the school weighs 150g, then the number of fish in the school is____.

  2. What should be subtracted from p and added to q so that the resulting ratio becomes 1 : 5?

  3. The cost of a pen is five times the cost of a pencil. I bought 8 pens and 4 pencils for Rs. 132. Find the cost of 5 pens and 5 pencils.

  4. Find the value of k, for which the system of equations kx + 3y = 26 and 21x + (k + 2)y = 71 + k has infinitely many solutions.

  5. Shaan got a total of Rs. 912 in the denomination of equal numbers of Rs. 1, Rs. 5 and Rs. 10 coins. How many coins do Shaan possess?

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