How do you evaluate #12[ \frac { x - 1} { 3} + \frac { 2x - 9} { 4} ]#?

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Answer 1 · 2017-09-06T19:01:43

See below.

Add the fractions inside the bracket.

#(x - 1)/3 + ( 2x - 9 )/4 #

The lowest common multiple of 3 and 4 is 12 so:

#(4( x - 1 ) + 3( 2x - 9 ))/12#

Multiplying out the numerator gives:

#(4x -4 + 6x -27)/12#

Collecting like terms:

#[(10x - 31 )/12]#

Multiply by 12

#cancel(12)[(10x - 31 )/cancel(12)]#

#10x - 31#