How do you solve # 4 /(x+1 )+ 3 /(x - 4) = 2 /( x +1)#?
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Assuming you want to solve for x, find the common denominator for the left side, #(x+1)(x-4)# and combine them into a single rational equation. Since #4/(x+1)# and #3/(x-4)# combine, it turns into #(7x-13)/((x+1)(x-4))# by multiplying the numerator #4*(x-4)# and #3*(x+1)#, adding them and combining like terms . You want to get rid of any denominators in the problem to make it simpler, so multiply that common denominator to both sides of the equation,
#(7x-13)/((x+1)(x-4))*(x+1)(x+4)# and same with the right side. On the left the common denominator gets cancelled so you're left with #7x-13#. On the right the #(x+1)# gets cancelled and you have #2(x-4)#. Multiply that and overall you have #7x-13=2x-8# left. then bring the #x's# on one side and the rest on the other side. #7x-2x=-8+13# , add and finally you have, #5x=5#, #x=1#. To check you can plug #x# in the original equation.
#4/(x+1)+3/(x-4)=2/(x+1)#
Our strategy will be to eliminate quotients.
This equation will look a lot less scary if we multiply both sides by #x+1#.
#4+(3(x+1))/(x-4)=2#
Now subtract 4 from both sides of the equation.
#(3(x+1))/(x-4)=-2#
Now multiply both side s of the equation by #x-4#.
#3(x+1)=-2(x-4)#
Hey! No more quotients! Now apply the distributive property.
#3x+3=-2x+8#
Add #2x# to both sides of this equation.
#5x+3=8#
Subtract 3 from both sides of this equation.
#5x=5#
Divide both sides of this equation by 5.
#x=1#
We can check our answer.
#4/(1+1)+3/(1-4)# =?= #2/(1+1)#
#4/2+3/-3# =?= #2/2#
#2-1# =?= #1#
#1=1#
Wadya know? Algebra WORKS!