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15 Flashcards in this deck.
Two-step linear equations are algebraic expressions that require two distinct operations to isolate the variable and solve for its value. Unlike one-step equations, which involve a single operation, two-step equations add a layer of complexity, making them an essential stepping stone in algebraic learning.
A typical two-step linear equation can be represented as: $$ ax + b = c $$ where a, b, and c are constants, and x is the variable to be solved.
Solving a two-step equation involves performing two inverse operations to isolate the variable. The general steps are:
Consider the equation: $$ 3x + 4 = 19 $$ To solve for x:
Thus, the solution is x = 5.
Suppose Sarah buys 3 notebooks and a pen for $19. If each notebook costs $3 and the pen costs $4, how much does each notebook cost?
Let x represent the cost of one notebook.
The equation representing the situation is: $$ 3x + 4 = 19 $$ Solving as before:
Each notebook costs $5.
It's crucial to verify solutions by substituting the value back into the original equation.
Using the first example, substitute x = 5: $$ 3(5) + 4 = 15 + 4 = 19 $$ Since both sides are equal, the solution is confirmed.
Two-step equations frequently appear in word problems, requiring students to translate real-world scenarios into mathematical expressions.
Example: A theater sells adult tickets for $12 each and child tickets for $8 each. If a total of 150 tickets were sold for $1,500, how many adult tickets were sold?
Let a represent the number of adult tickets and c represent the number of child tickets. The equations are: $$ a + c = 150 $$ $$ 12a + 8c = 1500 $$ Solving the first equation for c: $$ c = 150 - a $$ Substituting into the second equation: $$ 12a + 8(150 - a) = 1500 $$ $$ 12a + 1200 - 8a = 1500 $$ $$ 4a = 300 $$ $$ a = 75 $$
Thus, 75 adult tickets were sold.
Graphing two-step equations helps visualize the solution process. The equation $$ ax + b = c $$ can be rearranged to $$ ax = c - b $$ and then $$ x = \frac{c - b}{a} $$. Plotting this linear equation on a graph results in a straight line intersecting the x-axis at the solution point.
Two-step linear equations are not confined to pure mathematics; they have applications in economics, engineering, physics, and everyday problem-solving. For instance, calculating cost, determining distances, and optimizing resources often involve setting up and solving such equations.
While two-step equations involve a single equation, extending this knowledge to systems of equations introduces multiple variables and enhances problem-solving capabilities. Techniques such as substitution and elimination build upon the foundational skills acquired from solving two-step linear equations.
Aspect | One-Step Equations | Two-Step Equations |
Definition | Equations that require a single operation to solve for the variable. | Equations that require two distinct operations to isolate the variable. |
Complexity | Less complex, suitable for introductory algebra. | More complex, building upon foundational algebraic principles. |
Typical Form | $ax = b$ | $ax + b = c$ |
Solution Process | Use one inverse operation. | Perform two inverse operations sequentially. |
Example | $2x = 10$ | $3x + 4 = 19$ |
Applications | Basic problem-solving tasks. | More realistic and complex real-world scenarios. |
To excel in solving two-step equations, remember the acronym "PEMDAS" (Parentheses, Exponents, Multiplication and Division, Addition and Subtraction) to determine the order of operations. Additionally, double-check your solutions by substituting them back into the original equation, ensuring accuracy for AP exam success.
Two-step linear equations aren't just limited to textbooks! For example, architects use them to calculate dimensions and materials needed for building structures. Additionally, these equations play a role in determining budgets and expenses in personal finance, showcasing their relevance in everyday life.
Students often make errors such as forgetting to perform the same operation on both sides of the equation. For instance, in solving $$ 2x + 3 = 7 $$, a common mistake is subtracting 3 from only one side:
Incorrect: $2x + 3 = 7 \Rightarrow 2x = 7$
Correct: $2x + 3 = 7 \Rightarrow 2x = 4 \Rightarrow x = 2$