How do you solve #\frac { t + 5} { 2} + \frac { t } { 6} = \frac { t - 6} { 8} - 8#?

1 Answer
Apr 19, 2017

#t=-270/13=-20 10/13#

See the explanation.

Explanation:

Solve:

#(t+5)/2+t/6=(t-6)/8-8#

In order add or subtract fractions, they must have the same denominator, called the least common denominator (LCD). List the multiples of #2,6, and 8#.

#2:##2,4,6,8,10,12,14,16,18,20,22,color(red)24,26,28.....#
#6:##6,12,18,color(red)24,30,36.....#
#8:##8,16,color(red)24,32.....#

The LCD is #color(red)24#.

Now each fraction will need to be multiplied by an equivalent fraction that will result in a denominator of #color(red)24#. An #color(green)("equivalent fraction")# is equal to #color(green)1#. For example, #color(green)(2/2=1)#.

#(t+5)/2xxcolor(green)(12/12)+t/6xxcolor(green)(4/4)=(t-6)/8xxcolor(green)(3/3)-8/1xxcolor(green)(24/24)#

Simplify.

#(12(t+5))/24+(4t)/24=(3(t-6))/24-192/24#

#color(blue)(~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~#

Alternatively, you can skip multiplying by equivalent fractions, and multiply all terms by the LCD #24# directly.

#color(blue)(~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~#

Multiply each term by #24#.

#24((12(t+5))/24+(4t)/24=(3(t-6))/24-192/24)#

Simplify.

#12(t+5)+4t=3(t-6)-192#

Expand.

#12t+60+4t=3t-18-192#

Simplify.

#16t+60=3t-210#

Subtract #3t# from both sides.

#16t-3t+60=color(red)cancel(color(black)(3t))-210-color(red)cancel(color(black)(3t))#

Simplify.

#13t+60=-210#

Subtract #60# from both sides.

#13t+color(red)cancel(color(black)(60))-color(red)cancel(color(black)(60))=-210-60#

Simplify.

#13t=-270#

Divide both sides by #13#.

#t=-270/13=-20 10/13#