Cambridge International Mathematics

156 Formulae and simultaneous equations (Chapter 7)

Example 10 Self Tutor

Makexthe subject of T=

a

p

x

.

T=

a

p

x

) T^2 =

μ

a

p

x

¶ 2

) T^2 =

a^2

x

) T^2 x=a^2

) x=

a^2

T^2

fsquaring both sidesg

fmultiplying both sides byxg

fdividing both sides byT^2 g

Example 11 Self Tutor

Makexthe subject of T=

a

x¡b

:

T=

a

x¡b

) T(x¡b)=a

) Tx¡Tb=a

) Tx=a+Tb

) x=

a+Tb

T

fmultiplying both sides by(x¡b)g

fwriting term containingxon LHSg

fdividing both sides byTg

Example 12 Self Tutor

Makexthe subject of y=

3 x+2

x¡ 1

:

y=

3 x+2

x¡ 1

) y(x¡1) = 3x+2

) xy¡y=3x+2

) xy¡ 3 x=y+2

) x(y¡3) =y+2

) x=

y+2

y¡ 3

fmultiplying both sides by(x¡1)g

fwriting terms containingxon LHSg

fxis a common factorg

fdividing each side by(y¡3)g

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y:\HAESE\IGCSE01\IG01_07\156IGCSE01_07.CDR Friday, 10 October 2008 10:51:30 AM PETER