Page 82 - Mathematics

4b − 13a
=
= Example 5.9
20b
Therefore, Simplify the expression
b − 2a − b + 3a = 4b − 13a . 6m −− 15 and state the
4 2m +
4b 20b 20b coefficient of the variable m in the
simplified expression.

Example 5.8
Solution
6m – 4 – 2m + 15 = 6m – 2m + 15 – 4
Simplify the expression
3n − 7n + 12 .n = 4m + 11
The coefficient of m in the final
Tanzania Institute of Education
expression is 4.
Solution
3n − 7n + 12n = 3n + 12n − 7n
= 15n − 7n
= 8n
Therefore, 3n − 7n + 12n = 8 .n

Example 5.10

If m = 2, n = 4, and p = − 5, find the value of each of the following expressions.

3
(a) 3mn − 6mp + 2n p (b) m n − 2 2 p n + 2 3 7nmp
2
Solution
(a) 3mn − 6mp + 2n p 3
2
(5)
2
3
3mn − 6mp + 2n p = (3 2 4) (6 2 (5))× × + − × ×− + (2 4× 2 ×− 3 )
= 24 60 4000+ −
= − 3916
3
2
Therefore, the value of 3mn − 6mp + 2n p = − 3 916.
Mathematics Form One (b) m n − m n − p n + p n + 7nmp = = − 1816 2 ( 5) (4)− 2 3 + 7 4 2 ( 5)××× −
2
2 3
2
2
(2) (4) −
2
2
2 3
7nmp =

−
64 1 600 280−

Therefore, the value of m n −
2
2
p n +

76 2 3 7nmp is − 1 816.
25/10/2024 09:51:23
Mathematics form 1.indd 76 25/10/2024 09:51:23
Mathematics form 1.indd 76