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Wednesday, August 14th. Write an Equation: 4 less than a number is 10 2. Define the variables, constant, and coefficients -3x + 4y² + 12. Warm UP. Homework Answers. Translating Word Problems. What did Jose do wrong?. 5 less than a number 5 – x. Remember: LESS THAN
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Wednesday, August 14th • Write an Equation: 4 less than a number is 10 2. Define the variables, constant, and coefficients -3x + 4y² + 12 Warm UP
Homework Answers Translating Word Problems
What did Jose do wrong? 5 less than a number 5 – x Remember: LESS THAN First number goes last! X-5
Steps • Write Equation • Substitute number in and simplify
Example 1 Devon is 10 years older than twice Sammy’s age. If Sammy is 12, how old is Devon? Equation: D=10+2x D= 10 + 2(12) D=10 + 24 D=34
Example 2 Jessica is 5years younger than Mike’s age. If Mike is 23, how old is Devon? Equation: J=x-5 J= 23 - 5 J=18 j=18
Part 2: Consecutive equations The sum of 3 consecutive even numbers add up to 1002. Find the three numbers.
Consecutive Number Problems If the numbers are consecutive use: 1st number = x 2ndnumber = x + 1 3rdnumber = x + 2 etc
Consecutive Number Problems If the numbers are consecutive ODD: 1stnumber = x 2ndnumber = x + 2 3rdnumber = x + 4 etc
Consecutive Number Problems If the numbers are consecutive EVEN: 1stnumber = x 2ndnumber = x + 2 3rdnumber = x + 4 etc
Example 1 X + x + 2 + x + 4 = 1002 3x + 6 = 1002 3x = 996 X = 332 1st 332 2nd 334 3rd 336 The sum of 3 consecutive even numbers add up to 1002. Find the three numbers.
Example 2 1st 1201 2nd 1202 3rd 1203 4th 1204 The sum of 4 consecutive numbers add up to 4810. Find the four numbers.
Example 3 The sum of three consecutive number is 250. Find all three numbers.
A. Perimeter The distance AROUND an object. We must ADD all the sides! Think: The “fence” that goes around a shape. Equation: 2l + 2w=P l w w l
B. Area What COVERS a shape We must multiply two sides! Think: The “carpet that covers the shape Equation: l x w = A l w w l
Perimeter Problems Steps • Draw out rectangle • Label the sides • Add up the sides • Solve for x • Substitute x back into expression to find length and width
Example #1 The height of a rectangle is three centimeters more than twice its length. If the perimeter of the rectangle is 60 cm, what is its area? 1. Reasoning: Label the side lengths x and 2x + 3. 2. Add up the sides & solve: 2x + 4x + 6 = 60 ; x = 9 3. Substitute to find height. (2)(9) + 3 = 21. 4. Find the area of the rectangle. 5. Area is 189 cm squared.
Classwork Area and perimeter worksheet