How do you solve #3/(2x+10) + 5/4 = 7/(x+5)# for #x#?

1 Answer
Apr 20, 2017

#x=-3/5#

Explanation:

We need to get a common denominator for

#3/(2x+10)+5/4=7/(x+5)#

First, let's factor the denominators and see the components:

#3/(2(x+5))+5/(2*2)=7/(x+5)#

The common denominator will be #4(x+5)#

The first fraction needs a #2#, and if we multiply the second fraction (top and bottom) by #(x+5)# we should have a good start:

#3/(2(x+5))*(2)/(2)+5/(2*2)*(x+5)/(x+5)=7/(x+5)#

#6/(4(x+5))+(5x+25)/(4(x+5))=(7)/(x+5)#

Let's combine the two fractions:

#(6+5x+25)/(4(x+5))=7/(x+5)#

If we multiply #7/(x+5)# by #4/4#, both fractions will have the same denominator:

#(6+5x+25)/(4(x+5))=28/(4(x+5))#

Multiply by #(4(x+5))# on both sides and cancel denominators

#6+5x+25=28#

Combine like-terms

#31+5x=28#

Subtract #31# on both sides

#5x=-3#

Divide by #5# on both sides

#x=-3/5#