How do you solve 4/(b-3.9)=2/(b+1)?

1 Answer
Alan P.
Jul 29, 2017

color(green)(b=-5.9)

Explanation:

Given
color(white)("xxx")4/(b-3.9)=2/(b+1)

If we multiply both sides by (b-3.9)(b+1)
(sometimes called "cross-multiplying")
we get
color(white)("xxx")4(b+1)=2(b-3.9)

Expanding
color(white)("xxx")4b+4=2b-7.8

Simplifying
color(white)("xxx")2b=-11.8

color(white)("xxx")b=-5.9

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