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Linear Equations in One Variable. Objective: To find solutions of linear equations. Linear Equations in One Variable. An equation in x is a statement that two algebraic expressions are equal. For example, 3x – 5 = 7 is an equation. Solutions of Equations.
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Linear Equations in One Variable Objective: To find solutions of linear equations.
Linear Equations in One Variable An equation in x is a statement that two algebraic expressions are equal. For example, 3x – 5 = 7 is an equation.
Solutions of Equations • To solve an equation in x means to find all values of x for which the equation is true. Such values are called solutions.
Solutions of Equations • To solve an equation in x means to find all values of x for which the equation is true. Such values are called solutions. • For instance, x = 4 is the solution of the equation 3x – 5 = 7 since replacing x with 4 makes a true statement.
Identity vs. Conditional Equation • Identity-An equation that is true for every real number in the domain of the variable.
Identity vs. Conditional Equation • Identity-An equation that is true for every real number in the domain of the variable. • For example, is an identity since it is always true.
Identity vs. Conditional Equation • Conditional Equation-An equation that is true for just some (or even none) of the real numbers in the domain of the variable.
Identity vs. Conditional Equation • Conditional Equation-An equation that is true for just some (or even none) of the real numbers in the domain of the variable. • For example, is conditional because x = 3 and x = -3 are the only solutions.
Definition of a Linear Equation • A linear equation in one variablex is an equation that can be written in the standard form ax + b = 0, where a and b are real numbers and a cannot equal 0.
Example 1a • Solve the following linear equation.
Example 1a • Solve the following linear equation.
Example 1b • You Try • Solve the following linear equation.
Example 1b • You Try • Solve the following linear equation.
Example 2 • Solve the following linear equations.
Example 2 • Solve the following linear equations.
Example 2 • Solve the following linear equations.
Linear Equations in other forms • Some equations involve fractions. Our goal is to get rid of the fraction by multiplying by the common denominator.
Linear Equations in other forms • Some equations involve fractions. Our goal is to get rid of the fraction by multiplying by the common denominator. • The common denominator is 12. Multiply everything by 12.
Linear Equations in other forms • Some equations involve fractions. Our goal is to get rid of the fraction by multiplying by the common denominator. • The common denominator is 12. Multiply everything by 12.
Linear Equations in other forms • You Try. • Solve the following equation.
Linear Equations in other forms • You Try. • Solve the following equation.
Extraneous Solutions • When multiplying or dividing an equation by a variable expression, it is possible to introduce an extraneous solution. • An extraneous solution is one that you get by solving the equation but does not satisfy the original equation.
Example 4 • Solve the following.
Example 4 • Solve the following.
Example 4 • Solve the following.
Example 4 • Solve the following.
Example 4 • Solve the following. • If we try to replace each x value with x = -2, we will get a zero in the denominator of a fraction, which we cannot have. There are no solutions.
Example 4 • You Try • Solve the following.
Example 4 • You Try • Solve the following.
Intercepts • To find the x-intercepts, set y equal to zero and solve for x.
Intercepts • To find the x-intercepts, set y equal to zero and solve for x. • To find the y-intercepts, set x equal to zero and solve for y.
Intercepts • To find the x-intercepts, set y equal to zero and solve for x. • To find the y-intercepts, set x equal to zero and solve for y. • Find the x and y-intercepts for the following equation.
Intercepts • To find the x-intercepts, set y equal to zero and solve for x. • To find the y-intercepts, set x equal to zero and solve for y. • Find the x and y-intercepts for the following equation. • x-intercept (y = 0)
Intercepts • To find the x-intercepts, set y equal to zero and solve for x. • To find the y-intercepts, set x equal to zero and solve for y. • Find the x and y-intercepts for the following equation. • x-intercept (y = 0) • y-intercept (x = 0)
Intercepts • You Try • Find the x and y-intercepts for the following equation.
Intercepts • You Try • Find the x and y-intercepts for the following equation. • x-intercept (y = 0) • y-intercept (x = 0)
Class work • Pages 94-95 • 23, 25, 29, 31, 34, 35, 46, 47
Homework • Pages 94-95 • 3-36, multiples of 3 • 45-53 odd • 71,73,75