Chapter 10: Problem 18
Solve. $$\begin{aligned} &y=x^{2}\\\ &3 x=y+2 \end{aligned}$$
Short Answer
Expert verified
(1, 1) and (2, 4)
Step by step solution
01
Express y in terms of x
Given the first equation: \[ y = x^2 \] We already have y in terms of x.
02
Substitute y into the second equation
Substitute \( y = x^2 \) into the second equation: \[ 3x = y + 2 \rightarrow 3x = x^2 + 2 \]
03
Form a quadratic equation
Rearrange the equation to form a standard quadratic equation: \[ x^2 + 2 - 3x = 0 \rightarrow x^2 - 3x + 2 = 0 \]
04
Solve the quadratic equation
Solve the quadratic equation \( x^2 - 3x + 2 = 0 \) using factorization: \[ x^2 - 3x + 2 = (x - 1)(x - 2) = 0 \]Set each factor equal to zero: \[ x - 1 = 0 \rightarrow x = 1 \] \[ x - 2 = 0 \rightarrow x = 2 \]
05
Find the corresponding y values
Using the values of x, find y: For \( x = 1 \), \( y = 1^2 = 1 \) For \( x = 2 \), \( y = 2^2 = 4 \)
06
Write the solution as pairs
The solutions are the pairs \( (x, y) \): \( (1, 1) \) and \( (2, 4) \)
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Key Concepts
These are the key concepts you need to understand to accurately answer the question.
substitution method
The substitution method involves solving one of the equations in a system of equations for one variable in terms of the others. In this exercise, we start with the two equations:
- \(y = x^2\)
- \(3x = y + 2\)
quadratic factorization
After substitution, we obtain a quadratic equation, \(3x = x^2 + 2\). We rearrange it into the standard quadratic form:
- \(x^2 - 3x + 2 = 0\)
- \(x^2 - 3x + 2 = (x - 1)(x - 2) = 0\)
- \(x - 1 = 0 \rightarrow x = 1\)
- \(x - 2 = 0 \rightarrow x = 2\)
finding function pairs
Once we have the solutions for \(x\), the next step is to find the corresponding values of \(y\). By substituting \(x = 1\) and \(x = 2\) back into the first equation \(y = x^2\), we get the following pairs:
- For \(x = 1\), \(y = 1^2 = 1\), leading to the pair \((1, 1)\)
- For \(x = 2\), \(y = 2^2 = 4\), leading to the pair \((2, 4)\)
system of equations
A system of equations is a collection of two or more equations with the same set of variables. In this case, the system consists of:
- \(y = x^2\)
- \(3x = y + 2\)