Section 7 – 2 Solving Systems Using Substitution Objective: To solve systems using substitution
Investigation: Estimating Solutions
Substitution Method: A method for solving a system of equations in which one variable is replaced with an equivalent expression containing the other variable. Example: y = 3x + 2 4x + y = 9
Example 1 Using Substitution A) Solve using substitution. y = -4x + 8 y = x + 7
B) Solve using substitution. y = 2x + 2 y = -3x + 4
C) Solve using substitution. y = 3x – 1 y = -2x + 4
D) Solve using substitution. y = 4x + 7 y = -3x
1) y = x + 1 2) y = 2x + 5 y = 2x – 1 y = 6x + 1 3) 2y = x + 3 4) x – y = 1 x = y x = 1/2y + 2
Homework: Textbook Page 350; #5 – 10
Objective: To solve systems using substitution Section 7 – 2 Continued… Objective: To solve systems using substitution
Example 2 A) Solve using substitution. 2y = x + 3 x = y
B) Solve using substitution. x – y = 1 x = 1/2y + 2
C) Solve using substitution. y = 2x 7x – y = 15
D) Solve using substitution. y = -3x + 4 2x – y = 6
SPECIAL CASES Solve using substitution. 1) y = 3x – 6 2) x = y + 4 -3x + y = -6 y = x + 4
Classwork/Homework 7 – 2 Ditto: #1, 4, 7, 8, 9, 10
Answers to 7 – 1 Assignment 1) (1, 1) 4) (-3, 2) 7) (5, -2) 8) Infinitely Many 9) (100, 50) 10) No Solution
Section 7 – 2 Continued… (Day 3) Objective: To solve systems using substitution
Example 3 Using Substitution & the Distributive Property A) Solve using substitution. 6x + 6y = -6 5x + y = -13
B) Solve using substitution. 3x + y = 4 2x – y = 6
C) Solve using substitution. -5x + y = - 2 -3x + 6y = -12
D) Solve using substitution. -2x + y = -1 4x + 2y = 12
E) Solve using substitution. 3y + 2x = 4 -6x + y = -7
F) Solve using substitution. 6y + 8x = 28 3 = 2x – y
Section 7 – 2 Continued… (Day 4) Objective: To solve systems using substitution
Example 4 Real-World Problem Solving A) Your school committee is planning an after-school trip to take 193 students to a competition at another school. There are eight drivers available and two types of vehicles, school buses and minivans. The school buses seat 51 people each, and the minivans seat 8 people each. How many buses and minivans will be needed?
B). A youth group with 26 members is going to the beach B) A youth group with 26 members is going to the beach. There will also be five chaperones that will each drive a van or a car. Each van seats 7 persons, including the driver. Each car seats 5 persons, including the driver. How many vans and cars will be needed?
C). A rectangle is 4 times longer than it is wide C) A rectangle is 4 times longer than it is wide. The perimeter of the rectangle is 30 cm. Find the dimensions of the rectangle.
D). The length of a rectangle is 5 cm more than twice the width D) The length of a rectangle is 5 cm more than twice the width. The perimeter of the rectangle is 34 cm. Find the dimensions of the rectangle.