How to solve using quadratic formula: #(b/(x-a))+(a/(x-b)=2# ?

2 Answers
Nov 20, 2017

Multiply by x-a and x-b

Explanation:

Take note of the following before even using the quadratic formula:
x=a+b is one answer, as each fraction becomes b/b+a/a, which is two.

Step by step:

#(b/(x-a))+(a/(x-b))=2#
Multiply by x-a
#b+((a(x-a))/(x-b))=2(x-a)#
Multiply by x-b
#b(x-b)+a(x-a)=2(x-a)(x-b)#
Expand
#bx-b^2+ax-a^2=2x^2-2ax-2bx+2ab#
Collect like terms
#0=2x^2-3(a+b)x+(2ab+a^2+b^2)#
#0=2x^2-3(a+b)x+(a+b)^2#
There's a regular quadratic for you to solve using the quadratic formula.
for #dx^2+ex+f#, the solutions are #x=(-e+-sqrt(e^2-4df))/(2d)#
The solutions gotten:
#x=(3(a+b)+-sqrt(3^2(a+b)^2-4*2*(a+b)^2))/(2*2)#
#x=(3(a+b)+-sqrt(9(a+b)^2-8(a+b)^2))/(4)#
#x=(3(a+b)+-(a+b))/(4)#
The two solutions are therefore:
#x=(a+b)/2,a+b#

Nov 20, 2017

#x_1=(a+b)/2# and #x_2=a+b#

Explanation:

#b/(x-a)+a/(x-b)=2#

#[b*(x-b)+a*(x-a)]/[(x-a)*(x-b)]=2#

#(xb-b^2+ax-a^2)/[x^2-(a+b)*x+ab]=2#

#(a+b)*x-(a^2+b^2)=2x^2-(2a+2b)*x+2ab=0#

#2x^2-(3a+3b)*x+a^2+2ab+b^2=0#

#2x^2-(3a+3b)*x+(a+b)^2=0#

#[x-(a+b)]*[2x-(a+b)]=0#

Hence #x_1=(a+b)/2# and #x_2=a+b#