Chapter 12: Problem 10
Graph each equation of the system. Then solve the system to find the points of intersection. $$ \left\\{\begin{array}{l} y=\sqrt{x} \\ y=6-x \end{array}\right. $$
Short Answer
Expert verified
The points of intersection are (9, -3) and (4, 2).
Step by step solution
01
Graph the First Equation: y = sqrt(x)
Sketch the graph of the equation \( y = \sqrt{x} \). Start with some key points: when \( x = 0 \), \( y = 0 \); when \( x = 1 \), \( y = 1 \); when \( x = 4 \), \( y = 2 \), and so on. Plot these points on a coordinate plane and draw a curve passing through them.
02
Graph the Second Equation: y = 6 - x
Sketch the graph of the equation \( y = 6 - x \). This is a straight line. Calculate a few points by substituting values for \( x \). For instance: when \( x = 0 \), \( y = 6 \); when \( x = 6 \), \( y = 0 \). Plot these points and then draw the line.
03
Find the Points of Intersection
To find the points of intersection, set the two equations equal to each other: \( \sqrt{x} = 6 - x \). Square both sides to get rid of the square root: \(x = (6 - x)^2\). Expand and simplify it to find the values of \( x \).
04
Solve the Equation
Expand \( (6 - x)^2 \) to get \( x = 36 - 12x + x^2 \). Rearrange to form a quadratic equation: \( x^2 - 13x + 36 = 0 \). Solve this quadratic equation using the quadratic formula \( x = \frac{-b \pm \sqrt{b^2 - 4ac}}{2a} \). Here, \( a = 1 \), \( b = -13 \), and \( c = 36 \).
05
Find the Roots
Using the quadratic formula, calculate the roots: \( x = \frac{13 \pm \sqrt{169 - 144}}{2} \), which simplifies to \( x = \frac{13 \pm 5}{2} \). The solutions are \( x = 9 \) and \( x = 4 \).
06
Find the Corresponding y-values
Substitute back into either original equation to find the corresponding \( y \)-values. For \( x = 9 \), \( y = 6 - 9 = -3 \); For \( x = 4 \), \( y = \sqrt{4} = 2 \). Thus, the points of intersection are \( (9, -3) \) and \( (4, 2) \).
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Key Concepts
These are the key concepts you need to understand to accurately answer the question.
graphing equations
Graphing equations is a fundamental skill in math that helps visualize solutions. When you graph an equation, you plot points on a coordinate plane. Each point \(x, y\) satisfies the equation.
For example, to graph \(y = \sqrt{x}\), calculate values for \(y\) using different \(x\) values. When \(x = 0\), \(y = 0\); when \(x = 1\), \(y = 1\); when \(x = 4\), \(y = 2\).
Plot these on a graph and join them with a smooth curve.
Likewise, for a line like \(y = 6 - x\), pick \(x\)-values and compute \(y\): When \(x = 0\), \(y = 6\); when \(x = 6\), \(y = 0\).
Connect these points with a straight line.
For example, to graph \(y = \sqrt{x}\), calculate values for \(y\) using different \(x\) values. When \(x = 0\), \(y = 0\); when \(x = 1\), \(y = 1\); when \(x = 4\), \(y = 2\).
Plot these on a graph and join them with a smooth curve.
Likewise, for a line like \(y = 6 - x\), pick \(x\)-values and compute \(y\): When \(x = 0\), \(y = 6\); when \(x = 6\), \(y = 0\).
Connect these points with a straight line.
intersection points
Intersection points are where two graphs meet. These points represent solutions common to both equations.
To find them, set the equations equal. For \(y = \sqrt{x}\) and \(y = 6 - x\), set \(\sqrt{x} = 6 - x\).
Simplify and solve for \(x\): Square both sides to get \(x = (6 - x)^2\).
Expand to \(x = 36 - 12x + x^2\) and rearrange to form a quadratic equation: \(x^2 - 13x + 36 = 0\).
Solving this quadratic gives the \(x\)-values of the intersection points.
To find them, set the equations equal. For \(y = \sqrt{x}\) and \(y = 6 - x\), set \(\sqrt{x} = 6 - x\).
Simplify and solve for \(x\): Square both sides to get \(x = (6 - x)^2\).
Expand to \(x = 36 - 12x + x^2\) and rearrange to form a quadratic equation: \(x^2 - 13x + 36 = 0\).
Solving this quadratic gives the \(x\)-values of the intersection points.
quadratic equations
Quadratic equations involve terms with \(x^2\). They often appear when working with parabolas.
The standard form is \(ax^2 + bx + c = 0\). To solve, use the quadratic formula: \(\frac{-b \pm \sqrt{b^2 - 4ac}}{2a}\).
For \(x^2 - 13x + 36 = 0\), set \(a = 1\), \(b = -13\), and \(c = 36\).
Substitute into the formula to get \( \frac{13 \pm \sqrt{169 - 144}}{2} \), simplifying to \( \frac{13 \pm 5}{2} \).
Solving gives roots \(x = 9\) and \(x = 4\).
These are the \(x\)-coordinates for intersection points.
The standard form is \(ax^2 + bx + c = 0\). To solve, use the quadratic formula: \(\frac{-b \pm \sqrt{b^2 - 4ac}}{2a}\).
For \(x^2 - 13x + 36 = 0\), set \(a = 1\), \(b = -13\), and \(c = 36\).
Substitute into the formula to get \( \frac{13 \pm \sqrt{169 - 144}}{2} \), simplifying to \( \frac{13 \pm 5}{2} \).
Solving gives roots \(x = 9\) and \(x = 4\).
These are the \(x\)-coordinates for intersection points.
square root
The square root operation finds a number which, when multiplied by itself, equals the original number.
It’s indicated by \sqrt{}\.
For example, \( \sqrt{9} = 3 \) because \( 3 * 3 = 9 \. \)
In the equation \(y = \sqrt{x}\), \(y\) is the positive root of \(x\). To graph, calculate points: \( \)like for \( x = 4 \, y = \sqrt{4} = 2 \).
Solving an equation with square roots often involves squaring both sides, but introduces extra solutions needing verification.
Like in \( \sqrt{x} = 6 - x \), squaring gives \( x = (6 - x)^2 \).
It’s indicated by \sqrt{}\.
For example, \( \sqrt{9} = 3 \) because \( 3 * 3 = 9 \. \)
In the equation \(y = \sqrt{x}\), \(y\) is the positive root of \(x\). To graph, calculate points: \( \)like for \( x = 4 \, y = \sqrt{4} = 2 \).
Solving an equation with square roots often involves squaring both sides, but introduces extra solutions needing verification.
Like in \( \sqrt{x} = 6 - x \), squaring gives \( x = (6 - x)^2 \).