How do you solve (r+4)/3=r/5 and find any extraneous solutions?

1 Answer
Dec 24, 2016

r=-10

Explanation:

To ' eliminate' the fractions on both sides of the equation, multiply by the lowest common multiple (LCM ) of 3 and 5 which is 15

cancel(15)^5xx(r+4)/cancel(3)^1=cancel(15)^3xxr/cancel(5)^1

rArr5(r+4)=3rlarr" no fractions"

rArr5r+20=3r

subtract 3r from both sides.

5r-3r+20=cancel(3r)cancel(-3r)

rArr2r+20=0

subtract 20 from both sides.

2rcancel(+20)cancel(-20)=0-20

rArr2r=-20

To solve for r, divide both sides by 2

(cancel(2) r)/cancel(2)=(-20)/2

rArrr=-10" is the only solution"