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Ch. 1 - Equations and Inequalities
Blitzer - College Algebra 8th Edition
Blitzer8th EditionCollege AlgebraISBN: 9780136970514당신이 사용하는 게 아니라요?교과서 변경
2장, 문제 97a

Evaluate x2 - (xy - y) for x satisfying 3(x + 3)/5 = 2x + 6 and y satisfying - 2y - 10 = 5y + 18.

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Step 1: Solve for x in the equation \( \frac{3(x + 3)}{5} = 2x + 6 \). Start by eliminating the fraction by multiplying through by 5, resulting in \( 3(x + 3) = 5(2x + 6) \). Expand both sides to get \( 3x + 9 = 10x + 30 \).
Step 2: Rearrange the equation \( 3x + 9 = 10x + 30 \) to isolate x. Subtract \( 3x \) from both sides to get \( 9 = 7x + 30 \). Then subtract 30 from both sides to get \( -21 = 7x \). Finally, divide both sides by 7 to solve for x.
Step 3: Solve for y in the equation \( -2y - 10 = 5y + 18 \). Start by isolating y by adding \( 2y \) to both sides, resulting in \( -10 = 7y + 18 \). Subtract 18 from both sides to get \( -28 = 7y \). Finally, divide both sides by 7 to solve for y.
Step 4: Substitute the values of x and y into the expression \( x^2 - (xy - y) \). Start by calculating \( x^2 \), then calculate \( xy \), and finally calculate \( xy - y \).
Step 5: Subtract \( (xy - y) \) from \( x^2 \) to evaluate the expression. Simplify the result to complete the problem.

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주요 개념

질문에 올바르게 답하기 위해 반드시 이해해야 하는 핵심 개념들은 다음과 같습니다.

Solving Linear Equations

To evaluate the expression, we first need to solve the linear equations for x and y. A linear equation is an equation of the first degree, meaning it can be written in the form ax + b = 0. We can isolate the variable by performing algebraic operations, such as addition, subtraction, multiplication, or division, to find the values of x and y that satisfy the equations.
추천 영상:
04:02
Solving Linear Equations with Fractions

Substitution

Once we have the values of x and y, we can substitute these values into the expression x^2 - (xy - y). Substitution is a fundamental algebraic technique where we replace a variable with its corresponding value. This allows us to simplify the expression and compute the final result based on the values obtained from the linear equations.
추천 영상:
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Solving Systems of Equations - Substitution

Evaluating Expressions

Evaluating an expression involves calculating its value after substituting the variables with their respective numerical values. In this case, we will compute x^2 - (xy - y) using the values of x and y found earlier. Understanding how to correctly perform operations such as addition, subtraction, multiplication, and exponentiation is crucial for obtaining the correct final answer.
추천 영상:
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Evaluating Algebraic Expressions