SUBJECT: MATHEMATICS
CLASS: JSS 3
DATE:
TERM: 1st TERM
REFERENCE BOOKS
WEEK SEVEN
TOPIC: SOLVING EQUATION EXPRESSIONS
WORD PROBLEMS
Worked Examples:
Solutions:
1/4 of 18 = 4 2/5
xX 5 = 20 - 2x
5x = 20 - 2x
5x + 2x = 20
7x = 20
x = 20/7 = 2
sum of 35 and n = n + 35
divided by 4 = n + 35
4
result = 2 X n
thereforen + 35 = 2n
4
n + 35 = 8n
8n - n = 35
7n = 35
n = 35/7 = 5
EVALUATION
SOLVING EQUATION EXPRESSIONS WITH FRACTION
Always clear fractions before beginning to solve an equations: -
To clear fractions, multiply each term in the equation by the LCM of the denominations of the fractions.
Examples:
Solve the following
9
5 2
7 2
Solutions:
9
Cross multiply
x = 18
5 2
Multiply by the LCM (10)
10 X (x + 9) + 10 X ( 2 + x) = 0 X 10
5 2
2 (x + 9) + 5 (2 + x) = 0
2x + 18 + 10 + 5x = 0
2x + 5x + 28 = 0
7x = -28
x = -28/7 = -4
7 2
Multiply by the LCM (14)
14 X 2x = 14 (5x + 1) + 14 ( 3x - 5)
7 2
28x = 2 (5x + 1) + 7 (3x - 5)
28x = 10x + 2 + 21x - 35
28x = 31x - 33
28x - 31x = -33
-3x = -33
x = 33/3 = 11
EVALUATION
Solve the following equations.
y + 3 y - 2
2b - 5 b – 3
Furthermore, we can consider the word equations or expressions into:
SUM & DIFFERENCES
The sum of a set of numbers is a result obtained when the numbers are added together. The difference between two numbers is a result of subtracting one number from the other.
Worked Examples:
Solutions:
i.e Y = 7 + 7 = 14
M - (-3) = 8
m + 3 = 8
m = 8 - 3
m = +5
also -3 - m = 8
-m = 8 + 3
-m = 11
m = -11
the possible values are +5 & -11
1,3,5,7,9........... consecutive even numbers are 2, 4, 6, 8,10..........
Representing in terms of X, we have 2X, 2X + 2, 2X + 4, 2X + 6, 2X + 8, 2X + 10............
for consecutive even numbers, we have X, X + 2, X + 4, X + 6.......
for consecutive odd numbers, we have X + 1, X + 2, X + 3, X + 4...
for consecutive numbers.
let the first number be x,
let the second number be x + 1
let the third number be x + 2
Therefore x + x + 1 + x + 2 = 63
3x + 3 = 63
3x = 63 - 3
3x = 60
x = 60 /3
= 20
The numbers are 20, 21, and 22.
EVALUATION
PRODUCTS
The products of two or more numbers is the result obtained when the numbers are multiplied together.
Worked Examples:
Solutions
-6 x 7/10 x 20/3 = -6 x 7 x 20
10 x 3
= -2 x 7 x 2 = -28
X x = 8multiply both sides by 4
x = 8 x 4 = 33
Difference = -5-(-8) = -5 + 8 = 3
Products= 7 x 3 = 21
EVALUATION
READING ASSIGNMENT
New Gen Maths for J.S.S 3 Pg 20- 24
Essential Mathematics for J.S.S 3 Pg 85-87
WEEKEND ASSIGNMENT
(a) 20 years (b) 8 years (C) 10 years
answer is 5 what was the original number?
(a) 29 (b) 18 (c) 20
difference between their ages.
(a) 12 yrs (b) 15 yrs (c) 18 yrs
(a) 2 (b) 4 (c) 7
THEORY
1.Divide 36 by the difference between the product of 3 & 6 and the square root of 36.
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