Algebra I Concept Test # 8 – Writing Linear Equations Practice Test Use the given points to find the following: (8, 4) and (− 4, − 5) a) Find the slope of the line that goes through the two points. y2 – y1 m = Formula x2 – x1 4 – (− 5) m = Substitute 8 – (− 4) 4 + 5 m = Simplify 8 + 4 9 3 m = m = Reduce 12 4 © 2007-09 by S-Squared, Inc. All Rights Reserved.

Algebra I Concept Test # 8 – Writing Linear Equations Practice Test Use the given points to find the following: (8, 4) and (− 4, − 5) b) Find the y-intercept of the line that goes through the two points. Slope intercept form: y = mx + b Note: Substitute one of the given points and the calculated slope from part a into the slope intercept form of a linear equation to find b (the y-intercept). (4) = (8) + b 3 4 Substitute 4 = 6 + b Simplify – 6 – 6 Subtract − 2 = b y-intercept: (0, − 2)

Algebra I Concept Test # 8 – Writing Linear Equations Practice Test Use the given points to find the following: (8, 4) and (− 4, − 5) c) Write the equation in slope-intercept form. Slope – intercept form: y = mx + b 3 Slope m = 4 y-intercept y-intercept: (0, − 2) 1 2 3 4 5 − 1 − 2 − 3 − 4 − 5 3 4 Equation y = x – 2 4 d) Graph: 3 y-intercept: (0, − 2) 3 4 m =

Algebra I Concept Test # 8 – Writing Linear Equations Practice Test Use the given points to find the following: (8, 4) and (− 4, − 5) e) Write the equation in function notation. 3 y = x – 2 4 3 f (x) = x – 2 4 f) Find f (− 8) 3 4 f (− 8) = (− 8) – 2 Substitute f (− 8) = − 6 – 2 Simplify f (− 8) = − 8

Algebra I Concept Test # 8 – Writing Linear Equations Practice Test Given the following, write the equation of the line in slope-intercept form that passes through the given point and is: 2 5 y = x + 9 (10, 5) Slope – intercept form: y = mx + b a) Parallel to the given line. Note: Parallel lines have the same slope. 2 m = Given point: (10, 5) 5 2 5 5 = (10) + b Substitute 5 = 4 + b Simplify – 4 – 4 Subtract 1 = b 2 5 y = x + 1 Final Answer

Algebra I Concept Test # 8 – Writing Linear Equations Practice Test Given the following, write the equation of the line in slope-intercept form that passes through the given point and is: 2 Slope – intercept form: y = mx + b y = x + 9 (10, 5) 5 b) Perpendicular to the given line. Note: Perpendicular lines have opposite reciprocal slopes. − 5 m = Given point: (10, 5) 2 − 5 2 5 = (10) + b Substitute 5 = − 25 + b Simplify + 25 + 25 Add 30 = b − 5 2 y = x + 30 Final Answer

Algebra I Concept Test # 8 – Writing Linear Equations Practice Test Given the following, write the equation of the line in slope-intercept form that passes through the given point as is: 2 y = x + 9 (10, 5) 5 c) Write the given equation in standard form. Standard Form: Ax + By = C Where A, B, and C are integers 2 5 ( y = x + 9 ( ( ( 5 Multiply each term by the LCD 5 5 5y = 2x + 45 Subtract – 2x – 2x − 2x + 5y = 45

Algebra I Concept Test # 8 – Writing Linear Equations Practice Test 3. A group of adults and children attend the premiere of the ballet. An adult’s ticket cost $14.00 each and a child’s ticket cost $7.00 each. The total ticket sales equaled $420.00 a) Write an equation that represents the possible number of adult’s and children who attended. Assign variables: Let, a = the number of adults who attended c = the number of children who attended Set equal to the total 14a + 7c = 420

Algebra I Concept Test # 8 – Writing Linear Equations Practice Test 3. A group of adults and children attend the premiere of the ballet. An adult’s ticket cost $14.00 each and a child’s ticket cost $7.00 each. The total ticket sales equaled $420.00 b) If 40 children attended, how many adults attended? 14a + 7c = 420 Notice: c = the # of children who attended. Let, c = 40 14a + 7(40) = 420 Substitute 14a + 280 = 420 Simplify – 280 – 280 Subtract 14a = 140 Divide 14 14 a = 10 a = the # of adults who attended. 10 adults attended

Dreams are reality dressed as hard work. Algebra I Concept Test # 8 – Writing Linear Equations Practice Test 4. Given the graph below, write the equation of the line in slope – intercept form : Dreams are reality dressed as hard work. Slope – intercept form: y = mx + b Identify the y-intercept: 3 4 5 6 -4 -3 -2 -1 7 1 -7 -6 -5 2 b = 4 − 1 Identify the slope: 3 − 1 m = 3 − 1 Substitute y = x + 4 3