Page 102 - Mathematics_F1

5x +  2 ) y = 40 (5) 6.  0.7x −  0.5y = 2.5
  0.7x + 0.3y = 2.9
 5(x + 10 ) y = 120 (6)
 2x y+= 0
FOR ONLINE READING ONLY
Subtract equation (6) from (5): 7.  x − 2y = − 5 Tanzania Institute of Education
5x +  2 ) y = 40 
−   4 1
 5(x+ 10 ) y = 120  x + y = 3

5x – 5x + 2y – (+10y) = 40 – 120 8. 
 1 + 2 = − 1
2y – 10y = – 80  x y

–8y = – 80  8 12
 x − y = − 2

− 8y = − 80 . 9.  5 3
− 8 − 8  x + 2y = 1


Hence, y = 10.
0.2x +  0.3y = 0.1
Therefore, x = 4 and y = 10. 10. 
 0.3x − 0.1y = 0.7

0.05x +  0.02y = 0.01
Exercise 5.7 11. 
 0.02x − 0.03y = − 0.11
Solve the following simultaneous
equations by using elimination  1 x + 3y = 3


method. 12.  2
y
 2x += 5  3
1.    4 x − 2y = − 2
−=
 4x y 7
 3pq+ = 6 2v = 1
2.  13.  u +
 5pq+ = 8  3u − 4v = 8

5x −  2y = 16
3.   2pq+ = 4
 x + 2y = 8 14.  − 3p + 5q = − 19

8x +  5y = 40 
4. 
 9x − 5y = 5  2m +  1 n = 3 Mathematics Form One

7x −  4y = 17 15.  3
+=
5.   − 3mn 6

 5x − 4y = 11

95

25/09/2025 15:01:13
Mathematics form 1.indd 95
Mathematics form 1.indd 95 25/09/2025 15:01:13