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Algebra - Change Of Subject

Subject = ............

EXAMPLE
y = ............


Method Used: INVERSE OPERATIONS
Basic introduction: Operations And Inverse Operations


EXAMPLE
Make x the subject
y = x + 3

We require x to be the subject of the formula
The subject is written on the left
So we switch the sides to get x on the left
x + 3 = y

We require x by itself on the left hand side
But we have x + 3
The inverse of addition is subtraction
We need to subtract 3 from the left side
But, to keep the equality true, we need to subtract 3 from the right side as well
So subtract 3 from both sides
x + 3 - 3 = y - 3

Tidy up
x = y - 3




 

 

 



Edited by Dr David Cornelius an Independent Private Maths Tutor with over 25 years of experience and The Secretary of The Association of Tutors in the UK for 15 years.