algebra simultaneous equations

1. Solve the equation for x:
Solve the inequality for x:
Make x the subject of the formula:

2. By the end of the lesson you will be able to:
• Solve simultaneous equations by substitution
method .
Simultaneous equations.

3. The perimeter of a rectangle is 16 cm.
Its base is three times its height.
Using b to represent the length of the
base and h to represent the height of
the rectangle, write two equations that
represent the information given.
Find the dimensions of the rectangle.

4. 2 b + 2 h = 16
b = 3 h
Use the fact that b = 3 h to re­write
the first equation in terms of h only.
2 b + 2 h = 16
2 (3h) + 2 h = 16
Solve for h:
6 h + 2 h = 16
h = 2
Find b : b = 6
simultaneous
equations

5. 2 b + 2 h = 16
b = 3 h
This form of solving the simultaneous
equations is called substitution method.

6. Samuel bought 3 erasers and 2
pencils, he paid $9.50. Thomas bought
one pencil and one eraser and he paid
$4. Find the cost of each item.

7. Solve by substitution:
x = 3
y = ­ 4

8. Solve by substitution:
a= 3
b=11

9. Solve the simultaneous equations :
r = 8
s = 3

10. Solve by substitution:
x = ­ 3
y = 4

11. Solve by substitution:

12. The sum of two numbers is 3 and their difference is
1.8. Find the numbers.
x = 2.4
y = 0.6

13. Solve by substitution:
x = 4
y = ­ 3

14. Solve from book :
page 108

15. Attachments
Simultaneous equations inequalities 2009.doc