4. Friday, January 25, 2013
Change the subject of the following formulae to
the letter given in the brackets:
Example 2:
Example 1:
w = x + 5 y (x)
p = q − 27 (q)
− 5y
x + 5y = w
+ 27
q − 27 = p
q =p x =w
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5. Friday, January 25, 2013
Example 3: Example 4:
p = 2q (q ) 3m = 2n (n)
2q =p 2 n = 3m
q =p n = 3m
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7. Friday, January 25, 2013
Example 5: Example 6:
p = 2q − 27 (q ) w = 4 x + 5 y (x)
2q+ 27 = p
− 4x − 5y = w
+
2q =p 4x = w
p + 27 w − 5y
q = x =
4
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8. Friday, January 25, 2013
Example 7:
Example 8:
p = 2q − 27 (q )
2
2q + 27= p
− 27
2 w = x + 5 y (x)
3
3
x − 5y = w
+
2
2q 2
=p
2
q = p + 27
3
x =w
x = ( w − 5y ) 3
p + 27
q=
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10. Friday, January 25, 2013
Exercise
1. Make k the subject of the
following formulae
k
a. m = 4+
3
b. x = k +9 2
c. 6+ k = 2p
d. 4k = hk + 5
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11. Friday, January 25, 2013
Exercise
Page 161
Ex.7.2C
No. 1a,b,c,d,e,f,I,j,k
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12. Friday, January 25, 2013
ALGEBRAIC
FORMULAE
(Find the value of variable)
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13. Friday, January 25, 2013
Example 1 2
Given that V = s h , find the value of V when s=6 and h=9
1: 6 9
3
Solution:
3
1 2 1
V = s h V = × 36 × 9
3 3 1
1 V = 1× 36 × 3
V= X X
3 V = 108
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14. Friday, January 25, 2013
Example 1
Given that A = bh
2: , find the value of A when12 4
b=12 and
h=4 2
Solution:
2
1 1
A = bh A = ×12 × 4
2 2 1
1 A = 1×12 × 2
A= X X
2 A = 24
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15. Friday, January 25, 2013
Exercise:
1. Given that , find the value of I when P=2500, R=8 and T=2
PRT
I =
100
2. Given that , find the value of M when a=72 and b=28
M = 4a − 3b
3. Given that 1 , find the value of A when h=15, a=13 and b=21
A = h( a + b)
2
4. Given that y = mx + c , find the value of y when m= -2 ,x=5 and c= -4
5. Given that L = x + 2tx
2
, find the value of L when x= -3 and t = 4
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