
Andrew M. answered 01/29/18
Tutor
New to Wyzant
Mathematics - Algebra a Specialty / F.I.T. Grad - B.S. w/Honors
Original fraction: x/(x+1)
(x + 3)/(x+1+3) = (3/28)(x/(x+1))
(x+3)/(x+4) = 3x/(28(x+1))
3x(x+4) = 28(x+1)(x+3)
3x2 + 12x = 28(x2 + 4x + 3)
3x2 + 12x = 28x2 + 112x + 84
25x2 + 100x + 84 = 0
using quadratic equation with a=25, b=100, c=84
x = [-100 ±√(1002-4(25(84))]/(2(25))
Can you finish working the quadratic?