Transcript Word Problems - Numbers (ppt.)

CA Standards 9.0: Students solve a system of two linear equations in
two variables algebraically and are able to interpret the answer
graphically. Students are able to solve a system of two linear
inequalities in two variables and to sketch the solution sets.
Objective: (1) Students will solve word problems using systems of
equations.
Agenda: 12/08/2011
1.) Warm-up
2.) Answers to Homework
3.) Lesson:
Word Problems - Numbers (ppt.)
4.) Assignment
5.) STAY ON TASK!!!
Math ROCKS
8.4 Word Problems - Numbers
Notes: Word Problems
Type: Numbers
“is” means equal
Ex 1) The sum of two numbers is 16. Their difference is 8.
Find the two numbers.
Let x – Bigger Number
y – Smaller Number
x + y = 16
x–y=8
2x + 0 = 24
2
2
x = 12
x + y = 16
12 + y = 16
-12
-12
y=4
8.4 Word Problems - Numbers
You try:
“is” means equal
Ex 2) The sum of two numbers is 35. Their difference is 7.
Find the two numbers.
Let x – Bigger Number
y – Smaller Number
x + y = 35
x–y=7
2x + 0 = 42
2
2
x = 21
x + y = 35
21 + y = 35
-21
-21
y = 14
8.4 Word Problems - Numbers
Notes: Word Problems
Type: Numbers
Ex 3) The sum of two numbers is 25. When four times the
smaller number is subtracted from three times the larger
number, the result is 5. What is the larger of the two numbers?
4 x + y = 25
3x –4y = 5
4x + 4y = 100
3x – 4y = 5
Let x – Bigger Number
y – Smaller Number
7x + 0 = 105
7
7
x = 15
15 is the larger number!!
8.4 Word Problems - Numbers
You try:
Ex 4) The sum of two numbers is 18. When five times the
smaller number is subtracted from six times the larger number,
the result is 31. What is the larger of the two numbers?
5 x + y = 18
5x + 5y = 90
6x –5y = 31
6x – 5y = 31
Let x – Bigger Number
y – Smaller Number
11x + 0 = 121
11
11
x = 11
11 is the larger number!!
8.4 Word Problems - Numbers
Notes: Word Problems
Type: Numbers
Ex 5) The difference of two numbers is 9. Three times the
smaller number plus five times the larger number is 61. What
are the two numbers?
Let x – Bigger Number
3 x–y=9
3x – 3y = 27
+5x+3y = 61
5x + 3y = 61
8x + 0 = 88
8
8
x = 11
x–y=9
11 – y = 9
-11
-11
– y = -2
y=2
y – Smaller Number