## Algebra 1

$b=-\frac{2}{3}$
Use cross multiplication since the variable is in the numerator and denominator. $\frac{3b}{b-4}=\frac{3}{7}$ cross multiply $21b=3(b-4)$ distributive property $21b=3b-12$ subtract 3b from both sides $21b-3b=3b-12-3b$ combine like terms $18b=-12$ divide both sides by 18 $18b\div18=-12\div18$ $b=-\frac{2}{3}$