Transcript Changing the subject when it appears twice.

Changing the subject of a
formula 3 new subject appears twice
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Copyright © R F Barrow 2010, all rights reserved
Make x the subject of this formula
ax  7  3 x  d
a x  7  3x  d
 3x 
a x  3x  7  d
 7 
a x  3x  d  7
 factorise 
x  a  3  d  7
   a  3
x
d 7
a3
Make x the subject of this formula
c  2a x  b  d  5x 
c  2 ax  bd  5 bx
5 bx  2 ax  bd  c
x  5 b  2 a   bd  c
x
bd  c
5b  2 a
Make x the subject of this formula
y
2x  3
x4
y  x  4  2x  3
xy  4 y  2 x  3
xy  2 x  3  4 y
x y  2  3  4 y
x
3 4y
y2
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