How do you solve #b/2 - b/5 =6#?

1 Answer
Nov 4, 2016

Answer:

#b=20#

Takes longer to explain than do the actual maths.

Explanation:

Multiply by 1 and you do not change the overall value. However, 1 comes in many forms so you can change the way a number looks without changing its overall value.

#" "color(green)([b/2color(red)(xx1)]" "-" "[b/5color(red)(xx1)]=6)#

#" "color(green)([b/2color(red)(xx5/5)]" "-" "[b/5color(red)(xx2/2)]=6)#

#" "[(5b)/10]" "-" "[(2b)/10]" " = 6#

#" "(3b)/10" "=" "6#

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Multiply both sides by #color(red)(" " 10)#

#" "color(green)(color(red)(10xx)(3b)/10" "=" "color(red)(10xx)6 )#

#" "10/10xx3b" "=" "60#

#color(white)(.)#

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But #10/10=1#

#" "3b" "=" "60#

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Divide both sides by 3

#" "b" "=" "20#